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Can COVID-19 vaccines cause injuries and death?

Updated January 18, 2024

vaccine injury death

According to the U.S. Department of Health and Human Services, adverse events are classified into five grades. The guidelines are as follows:

Grade 1 - Considered mild or asymptomatic and no intervention is required.

Grade 2 - A moderate event but minimal, local or noninvasive interventions are indicated. In some situations, certain activities of daily living are limited (shopping, meal preparations, using the telephone).

Grade 3 - Considered a severe or medically significant adverse event but not one that is considered immediately life-threatening. In certain cases, hospitalization, including long-term hospitalization is needed. Grade 3 reactions are disabling and limit a person’s ability to perform activities of daily living (feeding self, bathing, self-care). 

Grade 4 - A life-threatening event where urgent intervention is required 

Grade 5 - Death related to an adverse event

Under EUA authority, the FDA Commissioner may permit “unapproved medical products or unapproved uses of approved medical products to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions caused by CBRN (CBRN = chemical, biological, radiological, nuclear) threat agents when there are no adequate, approved, and available alternatives.”1

Most COVID-19 vaccines in use in the United States have an EUA status. To learn more about EUA products and vaccines and consumer rights, visit NVIC’s FAQ on Emergency Use Vaccines (EUA) & Vaccine Injury Compensation.

Original Pfizer - BioNTech Vaccine Trial Safety Data

More than 50 percent of adult participants involved in the Phase 1/2 human trials of Pfizer and BioNTech’s experimental messenger RNA (ribonucleic acid) COVID-19 vaccine reported adverse reactions. The trial was conducted in May and June 2020, and involved 45 healthy adults between the ages of 18 and 55 years. Limitations of this data were noted as not accurately reflecting populations at highest risk for COVID-19. 

In the trials, 12 adults received a 10-microgram dose of the BNT162b1 vaccine, 12 adults were injected with a 30-µg dose, 12 received a 100-µg dose, while nine adults were given an inert saline placebo. Within seven days of vaccination, seven (58.3 percent) of the participants in the 10-µg group reported adverse reactions (pain) near the injection site and 24–or 100 percent–in the 30-µg and 100-µg groups and two (22.2 percent) in the placebo group reported reactions. Severe pain was reported by one participant who received 100-µg dose.   

Three weeks after the initial vaccination with the Pfizer-BioNTech experimental vaccine, all clinical trial participants were given a second dose of the vaccine at the same dosage. Of the participants in the 10-µg group, 8.3 percent developed fevers. Of those in the 30-µg group, 75 percent developed fevers. More than 50 percent of the adults, who were given either a 10-µg or 30-µg dose, experienced an adverse reaction such as sleep disturbances and fever. Two participants suffered severe reactions. A Grade 3 fever of over 101.3°F two days after vaccination was experienced by one adult in the 30-µg group and sleep disturbance one day after vaccination was experienced by one adult in the 100-µg group.   

Pfizer reported early U.S. Phase 3 clinical trials results in mid-September. Company executives presented safety data for 5,664 individuals between 18 and 64 years of age, and 1,816 persons between 65 and 85 years who received one dose. In the younger age category, 16 percent reported chills, 35 percent complained of headache and 38 percent reported fatigue following vaccination. Eleven percent or less suffered diarrhea, joint pain, or chills. Side effects were reportedly lower among persons aged 65 to 85 years. 

After the second vaccine dose, 36 percent of trial participants between the ages of 18 and 64 reported fatigue, while 28 percent reported a headache and 18 percent reported muscle pain. Most adverse effects following the second dose were reported as mild to moderate; however, some participants did experience severe or life-threatening adverse reactions. Severe side effects occurred more frequently after the second dose. 

On December 11, 2020, the FDA issued an Emergency Use Authorization (EUA) for Pfizer-BioNTech’s messenger RNA (mRNA) COVID-19 vaccine for use in persons 16 years of age and older. 

The most commonly reported side effects associated with the vaccine included injection site pain, fatigue, headache, muscle pain, chills, joint pain, fever, injection site swelling and redness, nausea, malaise, and swollen lymph nodes.   

Additional adverse events reported in clinical trials included 12 cases of appendicitis (eight in the vaccine group vs. four in the placebo group), 70 cases of lymphadenopathy (64 in the vaccine group vs. 6 in the placebo group), and four cases of Bell’s Palsy, all in the vaccine group. 

In the data released at the December 10, 2020 Vaccines and Related Biological Products Advisory Committee meeting, six deaths were reported to have occurred during the clinical trials, two in the vaccine arm and four in the placebo arm. Of the two deaths in the vaccine arm, one person was reported as having a cardiac arrest 62 days post Dose 2 and the other was reported as atherosclerotic disease and died three days after Dose 1. 

Excess Adverse Events in Pfizer-BioNTech Vaccine Clinical Trials

A study published in Vaccine in September 2022 found that participants who received an mRNA COVID-19 were at a higher risk of experiencing a serious adverse reaction. The risk of an adverse reaction was higher than what was initially estimated at the time that the Pfizer-BioNTech mRNA COVID-19 vaccine was granted the EUA. According to the study, there were 10.1 additional events for every 10,000 individuals vaccinated and that 1 in 800 adults who received the Pfizer-BioNTech mRNA COVID-19 vaccine experienced a serious adverse event. 

Study authors also found that the risk of trial participants suffering a vaccine adverse event was greater than the reduction in COVID-19 related hospitalizations. 


On May 10, 2021, the FDA expanded the EUA granted Pfizer/BioNTech to distribute its experimental mRNA vaccine in the U.S. to include administration to children as young as 12 years old  and the CDC’s ACIP voted to approve its use in this population on May 12, 2021. 

The approval for use in adolescents 12 to 15 years was based on a small clinical trial involving 2,260 teens, of which 1,131 received the vaccine and 1,129 received a saline placebo.  According to the FDA’s Fact Sheet for Healthcare Providers Administering Pfizer-BioNTech COVID-19 Vaccine, the most common reported adverse events in adolescents 12 through 15 year olds included injection site pain, fatigue, headache, chills, muscle pain, fever, joint pain, injection site swelling and redness, lymph node swelling, and nausea. 

During the clinical trial, nearly 11 percent of 12- to 15-year-olds experienced a severe or Grade 3 vaccine reaction, with one study participant experiencing a Grade 4 reaction of a fever of 40.4°C. Five adolescents who received the Pfizer vaccine experienced a serious adverse event (SAE) during the trial, however, none of these events were considered by clinical trial investigators to be related to vaccination. 


On October 29, 2021, the FDA authorized the use of a 10mcg dose of Pfizer-BioNTech COVID-19 mRNA vaccine in children 5 through 11 years of age. The vaccine was authorized to be administered intramuscularly as a two-dose series, three weeks apart.

The authorization of the vaccine was based on two cohort studies, involving 3,100 children who received the vaccine, and 1,538 children who received a placebo. Only 1,444 vaccine recipients were monitored for safety at least two months after the second vaccine dose. 

In the Cohort 1 study (C4591007) 1,518 children between the ages of 5 and 12 years received a vaccine dose, however, only 1,444 (95.1 percent) were followed for safety concerns at least two months after the second vaccine dose. The most frequently reported adverse events among Cohort 1 study participants included injection site pain (71 percent), fatigue (39.4 percent), and headache (28 percent). Most occurred after the second dose, and generally within two days of vaccination. Lymphadenopathy (swelling of the lymph nodes) was the most common unsolicited adverse event among children who received the vaccine (N=13 or 0.9 percent). Fourteen children who received the vaccine experienced a hypersensitivity reaction, compared to four children in the placebo group. These events primarily included dermatitis and rash. 

The Cohort 2 study involved 1,591 children who received the vaccine and 778 children who received the placebo. At the time of the data cutoff (Oct. 8, 2021), this population had only been monitored for 2.4 weeks post dose two. According to the FDA, data collection was ongoing. Among the 3,109 vaccine recipients in both Cohort studies, four serious adverse events occurred; however, all were considered by the trial investigators to be unrelated to vaccination. These included an upper limb fracture, an infection of the knee, a foreign body ingestion, and an epiphyseal fracture. One vaccine recipient, a six-year-old female, developed Henoch-Schonlein purpura 21 days post dose one but this adverse event was reported to be non-serious. No deaths occurred among any study participants. 

Additional unsolicited adverse events reported among vaccine recipients included swelling under the skin triggered by an allergic response (angioedema), administration site disorders, swelling of the face, skin and subcutaneous tissue disorders, urticaria, arthritis, musculoskeletal and connective tissue disorders, synovitis, eye disorder, conjunctivitis, injection site rash, skin and subcutaneous disorder, dermatitis, rash, and eczema. No cases of myocarditis or pericarditis were reported among study participants; however, there were 12 cases where chest pain was reported. Six cases occurred among those receiving the vaccine, and six among placebo recipients. 

There were no participants in Cohort 1 that withdrew from the clinical trial due to an adverse event; however, one participant in the Cohort 2 study withdrew following dose one due to fever and worsening of neutropenia (this individual had a prior diagnosis of benign transient neutropenia). 

Vulvar ulcers in adolescent girls between 12-16 years of age were also reported after the second dose of Pfizer-BioNTech COVID-19 vaccine. An April 2022 published case study found an association between the vaccine and genital ulcers, with symptoms presenting within 24 hours of vaccination. Additional reports of genital ulcers following vaccination have been reported in VAERS. 

On June 17, 2022, the FDA authorized use of a 3mcg dose of Pfizer-BioNTech COVID-19 vaccine for use in children six months through four years of age, to be given as a 3-dose series. According to the FDA, in children six through 23 months of age, the most common reported adverse events included fever and pain, redness, swelling and tenderness of the injection site, decreased appetite, and irritability. Similar reactions were noted among children ages two to four years of age, with the additional symptoms of chills, fever, and headache. 

Seventeen children aged six through 23 months of age experienced a serious adverse event (SAE) following receipt of the vaccine in clinical trials. SAEs included pneumonia, RSV bronchiolitis, gastroenteritis, rotavirus gastroenteritis, viral gastroenteritis, accidental overdose, febrile convulsion, seizure, lower respiratory tract infection, anal abcess, metapneumovirus infection, and anaphylaxis. According to the trial investigators, none of the SAEs were considered to be related to the vaccine. 

Twelve children aged two through four years of age were reported to have experience one or more SAEs during the clinical trial. These SAEs included dehydration, appendicitis, pain in the extremities, pyrexia, focal peritonitis, status epilepticus, epilepsy, febrile convulsion, viral gastroenteritis, rotavirus gastroenteritis, gastroenteritis, diarrhea, upper respiratory tract infection and lower respiratory tract infection. Trial investigators considered two SAEs, pyrexia and pain in the extremities, reported in a four-year-old trial participant, to be related to vaccination. This patient required treatment in the emergency department and hospitalization for several days due to persistant fever and moderate calf pain. 


According to data released May 31, 2024 by the CDC, reports received by VAERS for the Pfizer-BioNTech experimental COVID-19 vaccine totaled over 958,438 vaccine adverse events with 215,495 categorized as serious. Noted within these reports were 23,419 deaths; 50,439 permanent disabilities; 143,699 hospitalizations; 93,192 emergency room visits, and 26,916 life threatening events. Also noted in these reports were that 778 deaths reported were categorized as senior living administration, with 91 percent of overall reported deaths occurring in persons 65 years of age and older.

Even though the National Childhood Vaccine Injury Act of 1986 legally required pediatricians and other vaccine providers to report serious health problems following vaccination to VAERS, many doctors and other medical workers giving vaccines to children and adults fail to report vaccine-related health problem to VAERS. There is evidence to suggest that only between 1 and 10 percent of serious health problems that occur after use of prescription drugs or vaccines in the U.S. are ever reported to federal health officials who are responsible for regulating the safety of drugs and vaccines and issue national vaccine policy recommendations.      

Moderna COVID-19 Vaccine Trial Data in Adults

On May 18, 2020, Moderna, Inc. of Cambridge, Massachusetts announced that it had obtained “positive interim clinical data” from a Phase 1 human clinical trial of its experimental mRNA-1273 COVID-19 vaccine. However, four out of 45 healthy clinical trial participants experienced serious (Grade 3) vaccine reactions. 

Each of the 45 participants was given two doses of the Moderna vaccine about a month apart at dosage levels that were either 25, 100 or 250 micrograms (µg). The mRNA-1273 vaccine reportedly produced a “Grade 3 adverse event” in one participant who received doses of between 25 µg and 100 µg. That individual experienced Grade 3 erythema (a rash) around the injection site. A Grade 3 rash can include blistering, open ulcers, wet peeling (moist desquamation) or a serious rash over large areas of the body. 

Three participants in the clinical trial who received a vaccine dose of 250 µg experienced “Grade 3 systemic symptoms” following administration of the second dose. Moderna described these as the “most notable” of the adverse events and said that they had been “transient and self-resolving.”  

On July 27, 2020, the National Institutes of Health (NIH) announced that Phase 3 trials of Moderna’s mRNA-1273 had begun. According to the press release issued by NIH: 

“Trial volunteers will receive two intramuscular injections approximately 28 days apart. Participants will be randomly assigned 1:1 to receive either two 100 microgram (mcg) injections of mRNA-1273 or two shots of a saline placebo. The trial is blinded, so the investigators and the participants will not know who is assigned to which group.”

In September 2020, three participants involved in the Phase 3 trial reported suffering reactions such as high fever, headaches, body aches and exhaustion. One participant suffered a bad headache, chills, a fever (over 100°F), and shortness of breath after getting the second vaccine dose, and described symptoms as “full-on COVID-like symptoms.”  Another of the trial participants, a woman in her 50s from North Carolina, suffered a migraine that “left her exhausted and struggling to focus.” 

On November 16, 2020, Moderna reported that adverse reactions were generally mild or moderate, and included headache, fatigue, and injection site pain 

The FDA issued an EUA for Moderna’s COVID-19 vaccine on December 18, 2020. In its press release, the FDA reported that during clinical trials, common reactions following Moderna vaccination included injection site pain, headache, fatigue, joint and muscle pain, fever, nausea, vomiting, and swelling of the lymph nodes in the arm where the vaccine was given. Vaccine adverse events typically persisted for several days and were more common following the second dose of the two-dose series. 

Serious adverse events occurring at higher rates in the vaccine group included myocardial infarction, kidney stones, gall bladder inflammation and Bell’s Palsy. Seven serious adverse events occurred in the vaccine group following vaccination, with four considered by clinical trial investigators to be related to the vaccine. These included intractable nausea and vomiting, rheumatoid arthritis, and two incidents of facial swelling that occurred in persons who had previously received cosmetic injections of dermal fillers. 

Thirteen deaths were reported during the clinical trials, with six occurring in the vaccine group and seven in the placebo group. In the vaccine group, two individuals over the age of 75 years with a history of heart disease died of heart related complications, two individuals were found deceased at home and the exact cause was not determined (a 56-year-old with a history of hypertension and chronic back pain being treated with opioid medication died 37 days after dose 1 and a 70-year-old with a history of cardiac disease was found dead 57 days after dose 2). One vaccine recipient died of suicide 21 days after dose 1, and a 72-year-old vaccine recipient with a history of Crohn’s disease and short bowel syndrome who was hospitalized for acute kidney failure and thrombocytopenia developed complications resulting in multiorgan failure and death 40 days after dose 2. 

A study published in November 2021 in the New England Journal of Medicine that examined the Phase 3 clinical trials noted that there were 17 deaths in vaccine group and 16 deaths in the placebo group. Additionally, study authors reported that one COVID-19 related death occurred among Moderna vaccine recipients and three COVID-19 related deaths occurred among placebo recipients.   

Excess Adverse Events in Moderna Vaccine Clinical Trials

A study published in Vaccine in September 2022 found that participants who received an mRNA COVID-19 were at a higher risk of experiencing a serious adverse reaction. The risk of an adverse reaction was higher than what was initially estimated at the time of the Moderna mRNA COVID-19 vaccine EUA in December 2020. According to the study, there were 15.1 additional events for every 10,000 individuals vaccinated and that 1 in 800 adults who received the Moderna mRNA COVID-19 vaccine experienced a serious adverse event. 

Study authors also found that the risk of trial participants suffering a vaccine adverse event was greater than the reduction in COVID-19 related hospitalizations. 


In June 2022, the FDA authorized use of two doses of a 100mcg Moderna COVID-19 mRNA vaccine in adolescents 12 through 17 years of age and two doses of a 50mcg Moderna COVID-19 vaccine in children six through 11 years of age under EUA. According to the FDA, the most common adverse events reported after vaccination during clinical trials included injection site redness, pain, and swelling, fever, chills, headache, nausea, vomiting, muscle and joint pain, fatigue, and swollen lymph nodes in the same arm of the injection. 

Twelve vaccine recipients aged 12 through 17 years of age experienced cardiovascular symptoms (chest pain, shortness of breath, and palpitations). This included a 12-year-old male who was hospitalized with chest pain, shortness of breath and abnormal EKG, three additional cases of shortness of breath, seven reports of syncope, and one report of palpitations. Forty-nine events of hypersensitivity reactions occurred among 46 vaccine recipients, and reported as injection site rash, hypersensitivity, dermatitis, and urticaria. No cases of anaphylaxis were reported. Additional adverse events included appendicitis, depression/suicidal ideation, drug-induced liver injury, and surgical repair of pectus excavatum. 

Adverse events of clinical significance reported among six through 11-year-old children who received the vaccine included epilepsy and seizures, loss of taste and smell, Tourette’s Syndrome, chest pain, shortness of breath, palpitations, musculoskeletal chest pain, vasovagal syncope, upper abdominal pain, suicidal ideation, oppositional defiant disorder, disruptive mood disorder, gastrointestinal disorder, asthma, synovitis, neck pain, epiphyseal fracture, Kawasaki Disease, ileus, and bradycardia. 


In June 2022, the FDA authorized use of a 25mcg Moderna COVID-19 mRNA vaccine in infants and children ages six months through five years, to be given as a 2-dose series. According to the FDA, the most common adverse events reported after vaccination in clinical trials included redness, swelling, and pain at the injection site, fever and underarm (or groin) tenderness and swelling of lymph nodes in the same arm or leg as the injection. In children aged 37 months through five years, the most common adverse events included headache, muscle ache, joint stiffness, fatigue, chills, nausea and vomiting. Among children ages six through 36 months of age, the most commonly reported side effects also included loss of appetite, irritability and crying, and sleepiness.  

Adverse events of clinical significance reported among children aged two through five-years who received the vaccine included erythema multiforme, seizure, chest pain, food allergy (egg), urticaria, rash, conjunctivitis, anaphylaxis, seizure, dyspnea, mental status change, chest pain, metapneumovirus, rhinovirus infection, adenovirus infection, Epstein-Barr virus infection, viral pneumonia, urinary tract infection, bronchial hyperactivity, and humerus fracture. In children aged six through 23 months, additional adverse events that occurred during clinical trials included a diagnosis of Type 1 diabetes, pyrexia with febrile seizure, metapneumovirus infection, rhinovirus infection, mastoiditis, erythema multiforme, electrolyte imbalance, bronchiolitis, febrile convulsion, adenovirus infection, asthma, croup infection, viral gastroenteritis, and cough with wheezing and urticaria.

According to the federal vaccine adverse event reporting system (VAERS), as of CDC’s May 31, 2024 release of data there were a total of 558,825 reports submitted to VAERS associated with the experimental Moderna COVID-19 vaccine. Noted within these reports were 82,175 serious events including 10,951 deaths; 16,691 permanent disabilities; 57,677 hospitalizations; 16,440 emergency room visits; and 9,970 life threatening events. Of the deaths reported to VAERS, 726 were noted as senior living administration settings, with over 91 percent of overall reported deaths occurring in persons 65 years of age and older.


Health officials have cautioned that symptoms of adverse reactions following COVID-19 vaccination may overlap with those of COVID-19 illness and be difficult to distinguish. However, symptoms of loss of taste or smell, shortness of breath, cough, rhinorrhea or sore throat are not considered common vaccine reactions, and persons experiencing these symptoms post-vaccination may be positive for SARS-CoV-2 or another infection. 

Since the December 2020 EUA of COVID mRNA vaccines, additional serious adverse events have been identified and associated with use of the products.

COVID-19 mRNA Vaccines and Heart Inflammation

By the spring of 2021, multiple cases of pericarditis (inflammation of the membrane surrounding the heart) and myocarditis (inflammation of the heart muscle) following mRNA vaccination had been reported to health authorities.     Adolescents and young adult males were noted to be at highest risk, especially after the second dose. 

In data presented during the June 2021 Advisory Committee on Immunization Practices (ACIP) meeting, the CDC reported that in females between the age of 12 and 17 years, after the second dose, the case rate of myocarditis/ pericarditis was 9.1 per million doses administered. In males 12 to 17 years of age, however, the rate after the second vaccine dose was 66.7 per one million doses. Cases among females 18 to 24 years old after the second dose were reported at 5.5 per one million doses, while after dose two, males of the same age range were affected at a rate of 56.3 per one million doses. Most cases of myocarditis/pericarditis resulted in hospitalization, and while most were reported as being resolved, the long-term health outcomes were reported to be unknown.  

A January 2022 study conducted by the CDC and several universities found that the risk of myocarditis after receipt of an mRNA COVID-19 vaccine was 133 times higher than the normal risk of the heart condition in the general population. Most cases occurred among 16-17-year-old males following the second dose, at a rate of one in 9,500. The study also reported that 96 percent of individuals who developed myocarditis required hospitalization for their symptoms. While approximately 87 percent of persons hospitalized for myocarditis reported that symptoms had resolved at time of discharge from the hospital, the long-term effects are not known.  Additional studies have also associated mRNA vaccines with heart inflammation, with researchers reporting the need for further investigation.                       

A population-based cohort study published in the British Medical Journal in December 2021 found that the Moderna COVID-19 vaccine was four times more likely to cause heart inflammation than the Pfizer vaccine.  A study published in Nature Medicine in December 2021 reported that men under the age of 40 were more likely to develop myocarditis following Moderna vaccination than following SARS-CoV-2 infection. 

In October 2022, Dr. Joseph Ladapo, the Surgeon General of Florida recommended against the use of mRNA COVID-19 vaccine in males 18 to 39 years of age due to the risk of cardiac related deaths post-vaccination. According to an analysis of vaccinated Florida residents, males 18 to 39 years had an 84 percent increased risk of cardiac related death within 28 days of vaccination. 

The CDC, however, has declined to pause use or make changes to the vaccine recommendations, and they continue to report that the benefits to vaccination outweighed the risk. Additionally, they have stated that persons with a history of myocarditis and pericarditis can still receive an mRNA vaccine and persons who developed pericarditis after the first mRNA vaccine dose can choose to receive the second dose after symptoms resolve. The CDC has also advised that individuals who develop myocarditis after the first dose can consider a second dose of the vaccine under certain circumstances. No data has been provided to support this recommendation. 

Additional COVID-19 mRNA Vaccine Adverse Events

Since the issuance of the COVID-19 mRNA vaccines in December 2020, additional serious adverse events have been reported in the medical literature. These adverse events include shingles , Graves’ Disease (an autoimmune disorder affecting the thyroid),   blood clots,         stroke,       thrombocytopenia with thrombosis syndrome (TTS),   vaccine-induced immune thrombotic thrombocytopenia (VITT),          menstrual changes,   acute myocardial events,   kidney disorders,  erythema multiforme (allergic skin reaction characterized by red, raised, symmetrical areas over the entire body),  Central Nervous System (CNS) Demyelination, including multiple sclerosis (MS),  Hepatitis C reactivation,  Immune Thrombocytopenia (ITP),  Multisystem Inflammatory Syndrome (MIS),        tinnitus,    diabetes,    prion disease (a rare, fatal, transmissible spongiform encephalopathy),   functional neurological disorder,  capillary leak syndrome (a rare but serious condition where blood plasma leaks from the capillaries and causes a drop in blood pressure),  acquired hemophilia A (a rare autoimmune disorder),  Bell’s Palsy,  pemphigus vulgaris (rare auto-immune disease that causes blisters to the skin and mucous membranes),  Guillain Barre Syndrome (GBS),     transverse myelitis,  organ transplant rejection,    anaphylaxis,     and death.             

A report published in November 2022 in Clinical Research in Cardiology that reviewed autopsy reports of individuals who died suddenly in Germany concluded that COVID-19 vaccines were likely responsible for the sudden death. The researchers limited the study to individuals who did not have any underlying heart issues and those who died within 20 days of the first or second vaccine dose.   

Persons who have pre-existing immunity to SARS-CoV-2 may also be at increased risk of severe reactogenicity following mRNA COVID-19 vaccination. 

Children who receive the COVID-19 vaccine may be higher risk of illness from other viruses. An Australian study on 29 children aged 5 through 11 years who received the Pfizer COVID-19 vaccine were studied for their “in vitro cytokine responses” to several pathogens prior to and 28 days post-vaccination, with eight children also examined six months later. Researchers found a decrease in immune response to “S. aureusE. coliLmonocytogenes, BCG vaccine, H. influenzae, hepatitis B antigen, poly(I:C) and R848 stimulations” when compared to pre-vaccination. Researchers concluded that COVID-19 mRNA vaccines in children can alter cytokine responses to other viral pathogens and that repeated doses could place them at an increased risk of both viral and bacterial infections.   

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In the fall of 2022, the FDA issued EUAs to both Pfizer-BioNTech and Moderna for bivalent booster dose of COVID-19 mRNA vaccine, containing the original Wuhan strain and the BA.4 and BA.5 SARS-CoV-2 Omicron variant for use in all individuals six months of age and older. Clinical trials of the vaccine were not required by the FDA and no safety data is available to support the use of these experimental products.        

Similarly, in September 2023, the FDA approved use of updated COVID-19 vaccines for 2023-2024 containing the SARS-CoV-2 Omicron variant XBB.1.5. The FDA did not require clinical trials of these vaccines prior to their approval and authorization. 

Moderna, however, conducted a clinical trial involving 101 individuals previously vaccinated with 3 doses of the original monovalent COVID-19 vaccine and one dose of bivalent COVID-19 vaccine. In this study, fifty adult participants received a 50mcg dose of a monovalent COVID-19 vaccine containing the SARS-CoV-2 Omicron variant XBB.1.5 and fifty-one participants received a dose of a bivalent COVID-19 vaccine containing 25mcg of SARS-CoV-2 Omicron XBB.1.5 variant and 25mcg of Omicron BA.4/BA.5. According to the study, most clinical trial participants reported both localized and system adverse reactions following vaccination. Researchers, however, reported that no serious adverse events or deaths occurred among trial participants but data was limited to only 20-22 days post vaccination. 

Pfizer- BioNTech Bivalent COVID-19 mRNA Vaccine Adverse Events

In January 2023, the FDA and CDC announced that they were investigating a potential link between the Pfizer-BioNTech Bivalent mRNA COVID-19 vaccine containing the original SARS-CoV-2 strain and the Omicron BA.4/BA.4 variant and ischemic stroke in persons 65 years and older. The possible safety signal, which was detected in the CDC’s Vaccine Safety Datalink (VSD), found an increased risk of stroke within the first 21 days after vaccination when compared to day 22-42. 

Long-term follow-up of clinical trial participants to monitor for conditions such as cancer and autoimmune diseases will become difficult, if not impossible. In December 2020, Pfizer-BioNTech officials stated that they would begin offering the vaccine to placebo recipients by March 1, 2021, which was several months earlier than what they had originally planned for.  By mid- January 2021, Moderna had already begun offering the vaccine to some placebo group participants. 


On June 1, 2023, the FDA revoked the EUA for Johnson & Johnson/Janssen COVID-19 vaccine. According to the FDA, Janssen BioTech had requested the voluntary withdrawal of its COVID-19 vaccine due to lack of demand for new lots of the vaccine, the expiration of last vaccine lots purchased by the U.S. federal government, and the decision by company officials to decline to update the vaccine to target new and emerging COVID-19 strains. 

Janssen/Johnson & Johnson COVID-19 Vaccine Trial Data

In late September 2020, Janssen/Johnson & Johnson released results of the Phase 1/2a clinical trial for its Ad26.COV2.S vaccine. This study was a double-blind, randomized, placebo-controlled trial and included 796 participants divided into two groups consisting of 402 healthy adults 18 to 55 years of age in one group and 394 healthy elderly individuals 65 years of age and older in the other.

In this trial, the first group was broken out into cohort 1a and cohort 1b. The second group was cohort 3. Trial participants were administered a single intramuscular injection of Ad26.COV2.S at dose levels of either 5×1010 or 1×1011 viral particles (vp) per dose of vaccine.   

Approximately 58 percent of participants in cohorts 1a and 1b experienced a localized adverse event, while 64 percent of them also suffered systemic adverse events. Of the participants in cohort 3, 27 percent of them experienced a localized adverse event, and 36 percent suffered systemic events (e.g. fever, irritability, drowsiness, rash, etc.) Of healthy adults aged 18 to 55 years old in cohorts 1a and 1b, 19 percent came down with fevers, while four percent of the adults aged over 65 years old in cohort 3 developed fevers.    

The fevers reported by participants were considered mild or moderate and resolved within one to two days after vaccination. However, five percent (20 participants) of participants in cohorts 1a and 1b suffered from Grade 3 fevers of over 101.3°F.

A news report on the Janssen/Johnson & Johnson Phase 1/2a trial reported that

“[There were two severe adverse events recorded. One participant had hypotension; however, this effect is not related to vaccination as the participant had a history of hypotension. Another participant with fever was hospitalized as a suspected case of COVID-19; however, the fever resolved within 12 hours." 

The most common adverse events experienced by trial participants were headaches, muscle pain, fatigue and pain the injection site.    

On September 23, 2020, Janssen/Johnson & Johnson announced the start of its Phase 3 clinical trials. The trial, a randomized, double-blind, placebo-controlled study, would enroll up to 60,000 participants in three continents.  However, on October 12, 2020, all clinical trials stopped after a participant developed an “unexplained illness.”   Sources familiar with the event reported that a male in his 20’s had a stroke after receiving the experimental vaccine.  Clinical trials in the U.S resumed in late October 2020. 

On February 27, 2021, the FDA issued an EUA for Janssen/Johnson & Johnson’s experimental vaccine for use in persons 18 years of age and older. 

Common side effects reported after vaccine administration with the Janssen COVID-19 in clinical trials included injection site pain, headache, fatigue, myalgia, nausea, fever, injection site redness and swelling. 

According to the Fact Sheet for Healthcare Providers issued by the FDA, serious adverse effects (SAE) were reported in 0.4 percent of vaccine recipients and 0.4 percent of placebo recipients. Reported adverse events that occurred among the vaccinated included five cases of urticaria and an additional case of hypersensitivity that was not considered to be anaphylaxis. One vaccine participant reported severe pain in the injection arm that was not responsive to pain medication and another complained of fever, headache and weakness that resolved within three days. 

The Fact Sheet also reported more cases of thromboembolic events, pulmonary embolism, transverse sinus thrombosis, seizures, and tinnitus occurring in those who received the COVID-19 vaccine than those who received the placebo.

On April 13, 2021, the FDA and CDC paused use of the vaccine after serious blood clots were reported in women between the ages of 18 and 49.  By April 23, 2021, 15 cases and 3 deaths had been associated with the rare blood clot disorder, now referred to by health officials as thrombosis with thrombocytopenia syndrome (TTS). All cases were reported in women, with two occurring in women over 50 years of age. The CDC’s Advisory Committee on Immunization Practices (ACIP) voted to resume full use of the vaccine in all persons 18 years of age and older on April 23, 2021, by a vote of 10 to 4 (with one voting member abstaining due to a conflict of interest). Those who voted against the recommendation expressed concern regarding the lack of warning on the risk of TTS in women under 50 years of age.   

The FDA updated the Janssen/Johnson & Johnson’s COVID-19 Fact Sheet on April 23, 2021 and acknowledged that: 

“Reports of adverse events following use of the Janssen COVID-19 Vaccine under emergency use authorization suggest an increased risk of thrombosis involving the cerebral venous sinuses and other sites (including but not limited to the large blood vessels of the abdomen and the veins of the lower extremities) combined with thrombocytopenia and with onset of symptoms approximately one to two weeks after vaccination. Most cases of thrombosis with thrombocytopenia reported following the Janssen COVID-19 Vaccine have occurred in females ages 18 through 49 years; some have been fatal. The clinical course of these events shares features with autoimmune heparin-induced thrombocytopenia. In individuals with suspected thrombosis with thrombocytopenia following the Janssen COVID-19 Vaccine, the use of heparin may be harmful and alternative treatments may be needed. Consultation with hematology specialists is strongly recommended.”

By May 2021, there had been 28 cases of TTS and 3 deaths confirmed by the CDC to be related to the Johnson & Johnson/Janssen COVID-19 vaccine. Additionally, TTS has been reported in men and in women between 50 and 60, in addition to women between 18 and 49 years. 

Due to the risk of TTS following vaccination, ACIP voted in December 2021 to give a preferential recommendation to mRNA COVID-19 vaccines.  The CDC reports that TTS occurs at a rate of one case per 250,000 doses. 

In early September 2021, the European Medicines Agency reported that its Pharmacovigilance Risk Assessment Committee (PRAC) was investigating a link between the Janssen/Johnson & Johnson COVID-19 vaccine and venous thromboembolism (blood clots in the veins). According to PRAC, in the initial clinical trials of the vaccine, a higher rate of venous thromboembolism was noted in the vaccine group when compared to the placebo group.  

On July 13, 2021, the FDA announced revisions to the Fact Sheet for Healthcare Providers administering the Janssen/Johnson & Johnson COVID-19 vaccine and the Fact Sheet for Recipients and Caregivers to include information regarding an increased risk of Guillain-Barré Syndrome (GBS) following vaccination. GBS, a serious neurological disorder where the body’s immune system attacks the peripheral nervous system, can cause muscle weakness, paralysis, and even death. According to the press release, the FDA reported 100 cases of GBS following vaccination, with 95 considered serious and requiring hospitalization, and one death. Government health officials noted that there was insufficient evidence to establish a causal relationship between the Johnson & Johnson/Janssen COVID-19 vaccine and GBS, and reported that “the known and potential benefits clearly outweigh the known and potential risks.” 

According to the CDC, rates of GBS following the Janssen/Johnson & Johnson COVID-19 vaccine were 21 times higher than after mRNA COVID-19 vaccines in the first 21 days post vaccination. After 42 days post vaccination, rates of GBS following the Janssen/Johnson & Johnson COVID-19 vaccine were 11 times higher.

On January 11, 2022, the FDA updated the Johnson & Johnson/Janssen COVID-19 Vaccine Fact Sheet for Health Care Providers Administrating with information regarding the serious risk of Immune Thrombocytopenia (ITP) within 42 days of vaccination. ITP is a blood disorder that can cause excessive bruising and bleeding due to very low levels of platelets.168

In January 2022, the Pharmacovigilance and Risk Assessment Committee (PRAC) of the European Medicines Agency (EMA) reported that a reasonable association existed between the Janssen/Johnson & Johnson and AstraZeneca, an additional adenovirus vector COVID-19 vaccine and transverse myelitis (TM), a rare but serious condition that involves inflammation of the spinal cord. Symptoms of TM include tingling, numbness, pain or loss of pain sensation, limb weakness, and issues with bowel and bladder function. According to PRAC, 38 cases of TM have been reported following adenovirus vector vaccines – 25 following the AstraZeneca COVID-19 vaccine and 13 following the Johnson & Johnson/Janssen vaccine.169

As of the May 31, 2024 data release, vaccine adverse events submitted to VAERS associated with the Johnson & Johnson/Janssen COVID-19 vaccine totaled 99,420, with 17,685 noted as serious. Included in these reports were 2,882 deaths; 3,443 permanent disabilities; 10,955 emergency room visits, and 12,402 hospitalizations.

Novavax COVID-19 Vaccine Clinical Trial Data

Maryland-based Novavax Inc, a biotechnology company which, prior to its COVID-19 vaccine, had never successfully delivered a product to market,  developed an experimental vaccine using recombinant nanoparticle technology. Referred to as a protein subunit vaccine,  NVX‑CoV2373 contains Novavax’s patented saponin-based Matrix-M™ adjuvant designed to enhance the immune response and stimulate high levels of neutralizing antibodies. 

Matrix-M1 contains nm (nanometers) of nanoparticles composed of Quillaja saponins, phospholipid and cholesterol. Quillaja saponins are chemical compounds extracted from the soapbox tree and are used as emulsifiers in food additives and beverages. 

Phase 1/2 clinical trials involved 131 participants, with 83 administered the NVX-CoV2373 vaccine containing the Matrix-M1 adjuvant to help stimulate an immune response to produce a strong antibody response.  Of the remaining trial participants, 25 were given the NVX-CoV2373 vaccine without the Matrix-M1 adjuvant and 23 participants were given a placebo of sterile 0.9 percent normal saline. Participant received two intramuscular injections in the deltoid muscle administered three weeks apart. 

According to the results of the clinical trial, two of the 83 participants (one each in groups D and E) suffered “severe adverse events” (fatigue, headache, and malaise) after the first dose. Two participants—one each in groups A and E—had “reactogenicity events” (malaise, fatigue, and tenderness). Following administration of the second dose, one participant in group D had a “severe local event” (tenderness) and eight participants—one or two in each group—had “severe systemic events.” The most common of these severe systemic events were fatigue and joint pain. One participant in group D developed a fever greater than 100 °F. 

Phase 3 clinical trials of NVX-CoV2373 began in the United Kingdom in late September 2020. This trial, a randomized, placebo-controlled, observer-blinded trial, was expected to enroll up to 10,000 volunteers. 

On March 1, 2021, Novavax released pre-peer reviewed research results on their experimental NVX-CoV2373 vaccine. The Phase 2 component of their Phase 1/2 trial was a randomized placebo-controlled trial to identify dosing regimen for the vaccine.

Vaccine arms of about 250 participants received one or two intramuscular doses at 5-μg or 25-μg or placebo, 21 days apart. Subsequent to randomization, 45 percent of participants were 50 to 84 years of age, and side effects were reported as mild and lasted about three days, with intensification after the second dose with the higher dosage of the vaccine.

The lower dose antibody response was reported as 100 percent for all age groups with neutralizing antibody rates exceeding those present in convalescent sera. The study concluded by stating that the two-dose regimen at the lower dose of 5-μg was suited for young and old alike and was highly protective. 

In June 2022, the FDA’s Vaccine and Related Biologics Products Advisory Committee (VRBPAC) voted to recommend issuing Novavax an EUA for its COVID-19 vaccine for adults. VRBPAC made this recommendation despite the risks of myocarditis and pericarditis associated with the vaccine. 

The FDA issued Novavax an EUA for its COVID-19 vaccine on July 13, 2022,  which was followed by a recommendation for use by the CDC’s ACIP. Novavax was authorized for use in adults 18 years and older as a two-dose primary series who have not previous received a COVID-19 vaccine.  In August 2022, the FDA expanded use of the vaccine in persons 12 years of age and older. 

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According to the Fact Sheet for Health Care Providers administering Novavax COVID-19 vaccine, the most common side effects reported following vaccination were injection site pain and tenderness, malaise/fatigue, muscle pain, headache, joint pain, nausea/vomiting, injection site redness and swelling, and fever. Serious side effects reported following Novavax COVID-19 vaccine include myocarditis, pericarditis, hypersensitivity reactions, chills, injection site itching and swelling of the lymph nodes. 

Novavax COVID-19 vaccines have also been associated with an increased risk of myocarditis and pericarditis. Additional serious cardiac adverse events reported in vaccine recipients included cardiomyopathy, cardiac failure and congestive heart failure.  Novavax COVID-19 vaccines have also been linked to cholecystitis (inflammation of the gall bladder, thrombotic and embolic events, and Guillain Barre Syndrome (GBS).

As of the May 31, 2024 data release, vaccine adverse events submitted to VAERS associated with the Novavax COVID-19 vaccine totaled 500 with 73 noted as serious. Included in these reports were 12 life-threatening reports, 50 hospitalizations, 18 permanent disabilities and 5 deaths.

On Mar. 10, 2020, the Secretary of Health and Human Services (HHS) invoked the 2005 Public Readiness and Emergency Preparedness (PREP) Act, after declaring that the COVID-19 pandemic was a public health emergency. As a result, manufacturers of COVID-19 vaccines that have been developed to respond to the SARS-CoV-2 pandemic are considered public health emergency “countermeasures”. The PREP Act shields manufacturers and vaccine providers from liability and vaccine injury compensation claims will be processed by the Countermeasures Injury Compensation Program (CICP).     

All COVID-19 vaccines, including the licensed Pfizer and Moderna mRNA COVID-19 vaccines, are considered countermeasures. Persons harmed or who die as a result of vaccination may file for benefits through the CICP within one year of injury or death of a loved one. 

As of May 1, 2024, HRSA reports that 10,100 claims alleging injury or death following COVID-19 vaccines have been filed with the CICP. Additionally, 3,047 claims alleging injury or death following additional COVID-19 countermeasures (i.e. medications, treatments, testing) have also been filled. Of the 2,645 claims where HRSA has rendered a decision, only 51 claims were found to be eligible for compensation. Twelve claims have been compensated (nine for myocarditis, one for myopericarditis, one for syncope, and one for anaphylaxis following COVID-19 vaccination), 38 claims are pending a determination of benefits, and one claim has been found to have no eligible reported expenses.   The CICP has paid out a total of $43,386 for claims associated with COVID-19 vaccines as of May 1, 2024. 

HRSA has denied 2,594 claims, with 1,651 denied for missing the one-year filing deadline, 362 denied for non-receipt of medical records, 251 denied due to product considered ineligible for CICP benefits or due to non-specified reasons, and 330 claims denied due to the “standard of proof not met and/or covered injury not sustained.” 

IMPORTANT NOTE: NVIC encourages you to become fully informed about COVID-19 and the COVID-19 vaccine by reading all sections in the table of contents, which contains many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.

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