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Quick Facts


  • Respiratory diphtheria is a rare bacterial infection with symptoms occurring 2-5 days after exposure. Symptoms include a sore throat, croupy cough, low-grade fever, runny nose, breathing problems and a fiber like coating on the tonsils, pharynx, or inside of nose. Neck swelling (bull neck) is usually present in severe disease. Complications include heart inflammation (myocarditis), neurologic inflammation (polyneuritis), kidney damage, and airway obstruction. Death occurs in 5%-10% of respiratory cases.
  • Cutaneous diphtheria is more rare than respiratory diphtheria and presents as infected skin lesions that lack a uniform appearance. Complications and death occur less frequently from this form of diphtheria.
  • Transmission requires direct person-to-person contact with respiratory secretions and cutaneous lesions and has been associated with poor sanitation, poverty and crowded living conditions. The last confirmed case in the U.S. was in 2003, with approximately 0-5 cases occurring per 100,000 individuals in the U.S. since 1980. 
  • Antibiotics are used in the treatment of the disease, but have had little effect and appear to only assist in decreasing its spread from infected individuals.
  • Some infected individuals may require hospitalization to maintain hydration and to monitor breathing and heart function.
  • Diphtheria can reoccur in individuals who have already had the disease.

Diphtheria Vaccine

  • The vaccine is a “combination” vaccine, meaning it is given together with two or more other vaccines. Check with your health care provider about which vaccine is being administered. See FDA below for information on combination vaccines containing diphtheria.
  • Adverse reactions to combination vaccines include: temperature of 105F or higher, collapse/shock, persistent crying, convulsions, coma, uncontrolled epilepsy, progressive encephalopathy and death. 
  • Transmission of diphtheria can occur in vaccinated individuals who become asymptomatic carriers of the disease as a result of the vaccine.
  • As with any vaccine, immunity wanes over time. The CDC recommends adults get booster shots every 10 years.
  • Using the MedAlerts search engine, as of March 31, 2020, there have been more than 187,344 reports of diphtheria vaccine reactions, hospitalizations, injuries and deaths following diphtheria vaccinations made to the federal Vaccine Adverse Events Reporting System (VAERS), including 3,207 related deaths, 22,619 hospitalizations, and 3,292 related disabilities. Over 60% of those diphtheria vaccine-related adverse events occurring in children under six years old. Some of the adverse reactions of the combination vaccines containing diphtheria include temperature of 105 F. or higher, collapse or shock-like state (hypotonic-hyporesponsive episodes), persistent crying lasting 3 hours or more, convulsions with or without fever, and encephalopathy (coma, decreased level of consciousness, prolonged convulsions).
  • As of May 1, 2020, there had been 5,879 claims filed in the federal Vaccine Injury Compensation Program (VICP) for injuries and deaths following Diphtheria vaccination, including 867 deaths and 5,012 serious injuries.

Food & Drug Administration (FDA)

Centers for Disease Control (CDC)

Vaccine Reaction Symptoms & Ingredients

Our Ask 8, If You Vaccinate webpage contains vaccine reaction symptoms and more. 

Search for Vaccine Reactions

NVIC hosts MedAlerts, a powerful VAERS database search engine. MedAlerts examines symptoms, reactions, vaccines, dates, places, and more.

Reporting a Vaccine Reaction

Since 1982, the NVIC has operated a Vaccine Reaction Registry, which has served as a watchdog on VAERS. Reporting vaccine reactions to VAERS is the law. If your doctor will not report a reaction, you have the right to report a suspected vaccine reaction to VAERS.

IMPORTANT NOTE: NVIC encourages you to become fully informed about Diphtheria and the Diphtheria vaccine by reading all sections in the Table of Contents , which contain 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.

What is Diphtheria?

Diphtheria is a rare respiratory disease caused by bacteria and the mucus membranes of the body. It begins with a gradual onset of a sore throat and low-grade fever and can involve the tonsils and nose.  

Diphtheria causes a gray-green to black, thick fiber-like covering in the back of the throat. Neck swelling is usually present in severe cases. Diphtheria can lead to breathing problems, airway obstruction, paralysis, heart failure, coma and even death if not treated promptly.  

Cutaneous (skin) diphtheria presents as skin lesions.  

Diphtheria is an extremely rare disease in modern, developed countries with good sanitation. When outbreaks of diphtheria do occur, they almost always erupt in areas of poor sanitation and poverty.  

Cases of diphtheria are so rare in both the US and other developed nations that, unless you are traveling to an impoverished country or a location of a natural disaster that has compromised the sanitation infrastructure, the danger of you or child getting diphtheria is very remote.   

Diphtheria can reoccur in individuals who have already had the disease.  

Symptoms of diphtheria usually appear two to five days after you come in contact with the bacteria and include:

Can Diphtheria Cause Injury and/or Death?

Yes. There is a gap in medical knowledge in terms of predicting who will have a mild case of diphtheria and who will have a serious or even deadly case of it. Complications from diphtheria can cause myocarditis (inflammation of the heart wall), paralysis, and polyneuritis (inflammatory lesions of multiple nerves), as well as airway obstruction. Diphtheria also can damage the kidneys.  

According to the CDC, in the early part of the 20th century, the US saw 100-200 cases per 100,000 people. Today respiratory diphtheria cases are approximately 0.001 cases per 100,000 – in other words, zero to five cases per year, nationally. Between 1998 and 2003, just seven cases, total, were reported to the CDC. (see this link)

The World Health Organization’s latest figures (2017) on worldwide incidence are reported to be 8,819 diphtheria cases. 

How Do You Get Diphtheria?

Diphtheria spreads through respiratory droplets produced by a cough or sneeze from an infected person, or from someone who carries the bacteria, but has no symptoms; for example, vaccinated individuals can become asymptomatic carriers (see “How Effective Is the Diphtheria Vaccine?” below). Also, according to the National Institutes of Health (NIH), diphtheria can be spread by contaminated objects such as handkerchiefs or tissues, or through foods, such as contaminated milk.  

Once infected, dangerous substances called toxins produced by the bacteria can spread through your bloodstream to other organs, such as the heart, and cause significant damage. Diphtheria can reoccur in individuals who have already had the disease.  

Diphtheria has been associated with poor sanitation, poverty and crowded living conditions. In a diphtheria outbreak in the Russian Federation in the 1990s, additional significant contributing factors included exposure to skin lesions and a history of eczema, sharing a bed, sharing glasses and cups, and taking a bath less often than weekly.1

According to Harrison’s Principles of Internal Medicine1, an outbreak of diphtheria in Seattle, Washington between 1972 and 1982 showed that significant risk factors for the disease in this instance were alcoholism, low socioeconomic status, crowded living conditions, and Native-American ethnic background. 

How Do You Treat Diphtheria?

According to the NIH, diphtheria antitoxin is given as a shot into a muscle or through an IV (intravenous line). Most infected persons are given antibiotics, such as penicillin and erythromycin.  

People with diphtheria may also need to stay in the hospital while the antitoxin is being received. Other treatments may include:

  • Fluids by IV
  • Oxygen
  • Bed rest
  • Heart monitoring
  • Insertion of a breathing tube
  • Correction of airway blockages

The NIH also says that anyone who has come into contact with the infected person should receive an immunization or booster shots against diphtheria. The vaccine lasts only 10 years from the time of vaccination and booster doses are given to adults every 10 years.   

According to Harrison’s Principles of Internal Medicine1, antibiotics have demonstrated little effect on the healing of local infection in diphtheria patients; the primary goal of the antibiotic therapy is to prevent transmission of the disease to susceptible contacts.  

Possible Side Effects from Treatment for Diphtheria: According to Harrison’s Principles of Internal Medicine1, since diphtheria antitoxin is produced in horses, it is necessary to question patients about possible allergy to horse serum, and to perform a test for possible hypersensitivity to the antitoxin.

Antibiotic Side Effects: All pharmaceutical products, including antibiotics, like all vaccines, carry an inherent risk of injury or death for some individuals. 

It is important to be aware of potential side effects. Overuse of antibiotics and use of antibiotics in the absence of bacterial infection has contributed to the development of antibiotic-resistant strains of organisms that can cause life-threatening illness.  This has made it necessary to develop more powerful antibiotics, some of which carry serious side effects.  

In addition to killing unwanted toxic bacteria, such as diphtheria, antibiotics also kill the normal flora of the gastrointestinal tract and can cause nausea, diarrhea, vomiting and yeast infections. Rashes, hives, and other allergic reactions, including anaphylactic shock leading to death, can occur.

Some antibiotics can cause central nervous system problems, including severe headaches, drowsiness, dizziness, irritability and restlessness, nerve paralysis and seizures.  Other antibiotic reactions include blood disorders, such as anemia and thrombocytopenia (which can lead to uncontrolled bleeding); kidney and liver dysfunction and serum sickness that cause fatigue, muscle weakness and painful joints. 

What Is the Diphtheria Vaccine?

A vaccine against diphtheria alone is not available in the U.S. However, there are several combination vaccines with diphtheria in them. These vaccine combinations and links to the package inserts and licensing information are in the Quick Facts section at the top of this webpage and are provided by the Food and Drug Administration. DTP is an older version of the DTaP combination vaccine that is no longer used in the U.S. but is still used in many other countries, particularly underdeveloped nations

The manufacturer’s product package insert will also give you more information about (1) reported adverse health outcomes, including injuries and deaths reported in pre-licensure clinical trials and post-marketing surveillance; and (2) reasons why your child should not use a particular diphtheria containing vaccine (contraindication) according to the vaccine’s manufacturer (3) and administration information such as age and dosage.    

You can ask your physician (or vaccine administrator) for the manufacturer product information package insert. Under federal vaccine safety law, your doctor or vaccine provider should be giving you the CDC’s Vaccine Information Statement (VIS) to read BEFORE you or your child are vaccinated. We provide a link to the CDC’s VIS in our Quick Facts section at the top of this page under CDC.   

NVIC Note: There are some doctors who either administer vaccines singly or limit the numbers of vaccines given simultaneously.

The CDC’s Advisory Committee on Immunization Practices (ACIP) recommends 6 doses of diphtheria and tetanus toxoids and acellular pertussis (DTaP/Tdap) vaccine for infants and older children. After that, the ACIP recommends boosters of DT (diphtheria-tetanus) every 10 years for adults.  

Diphtheria vaccine is required in all states. For more information about which vaccines your state requires, visit our State Vaccine Laws webpage.

How Effective Is the Diphtheria Vaccine?

According to the CDC, vaccinated individuals can still be asymptomatic carriers of diphtheria. Like with every vaccine, vaccine induced immunity wanes over time. The CDC recommends adults get booster shots every 10 years.

Can the Diphtheria Vaccine Cause Injury and/or Death?

Yes. There is a gap in medical knowledge in terms of predicting who will have an adverse reaction to the diphtheria containing vaccines and who will not.  

See the vaccine manufacturers’ package insert links above in our Quick Facts and examine the “contraindications, warnings and precautions, and adverse reactions,” contained in the insert to become better informed about the benefits and risks of diphtheria containing vaccines.  

Some of the adverse reactions of the combination vaccines containing diphtheria are as follows:

  • Temperature of 105 F. or higher within 48 hours of a previous pertussis vaccination, not attributable to another identifiable cause
  • Collapse or shock-like state (hypotonic-hyporesponsive episodes) within 48 hours of a previous pertussis vaccination
  • Persistent crying lasting 3 hours or more within 48 hours of a previous pertussis vaccination
  • Convulsions with or without fever, occurring within 3 days of a previous pertussis vaccination
  • Serious allergic reaction to a pervious pertussis vaccination
  • Encephalopathy (coma, decreased level of consciousness, prolonged convulsions) within 7 days of a previous pertussis vaccination not attributable to another identifiable cause
  • Children with a progressive neurologic disorder (such as infantile spasms, uncontrolled epilepsy, or progressive encephalopathy)

For more information on adverse reactions from combination pertussis, diphtheria and tetanus vaccines, visit the NVIC pertussis (whooping cough) webpage.


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