How Effective is Hib Vaccine?
The Hib vaccine in general provides titer (antibody) levels indicating protection against invasive Hib in about 90 to 95 percent of infants who have received two to three doses of the vaccine.
There is some evidence that suggests that giving Hib conjugate vaccines to infants before the age of 6 weeks old may reduce the vaccine’s effectiveness overall when the second and third doses are given. Efficacy studies have not been done in populations with increased risk of invasive disease (for example, immunocompromised invidivudals).
Even so, according to the CDC, Hib vaccine offers protection to patients with increased risk of getting this disease, including those with sickle-cell disease, leukemia, and those who have had a splenectomy. For those who have human immunodeficiency virus (HIV), the vaccine’s effectiveness varies with the stage of infection and degree of immunocompromise.1,2
- ActHIB — According to the manufacturer’s product insert, ActHIB induces antibodies in 90 percent of infants after the primary series and 98 percent of infants after a booster dose. However, Native Americans, who have been noted to have high rates of Hib, also have low immune responses to the Hib conjugate vaccines. The manufacturer reports that following a full three doses of the vaccine between 6 weeks and 6 months of age, only 75 percent of Native American infants had acceptable antibody levels. In children with sickle cell anemia, two doses of ActHIB produced acceptable antibodies in 89 percent of children.
Also, if ActHIB or ActHIB reconstituted with DTP or Tripedia is administered to immunosuppressed person receiving immunosuppressive therapy, expected antibody responses may not be obtained. This includes patients with asymptomatic or symptomatic HIV-infection, severe combined immunodeficiency, hypogammaglobulinemia or agammaglobulinemia; altered immune status due to diseases such as leukemia, lymphoma, or generalized malignancy, or an immune system compromised by treatment with corticosteroids, alkylating drugs, antimetabolites or radiation.
ActHIB has been found to be effective in children with sickle cell anemia. Antibody levels associated with protection against Hib with this vaccine may not be achieved until two weeks following the last recommended dose; ActHIB may not protect 100 percent of individuals. Additionally, persons who have been vaccinated with polysaccharide vaccines like ActHIB may still get HIB after vaccination and before the protective effects of the vaccine begin.3
- Hiberix — According to the manufacturer’s product insert, neither safety nor effectiveness of Hiberix in immunosuppressed children has been evaluated. If Hiberix is administered to immunosuppressed children, including those receiving immunosuppressive therapy, the expected immune response may not be obtained. Immunosuppressive therapies that may reduce immune response to Hiberix include irradiation, antimetabolites, alkylating agents, cytotoxic drugs and corticosteroids used in greater than physiologic doses. Vaccination with Hiberix does not substitute for a routine tetanus vaccine. Also, there is not enough data available to confirm whether administering Hiberix at the same time as other vaccines could interfere with immune responses to those vaccines. In clinical trials effectiveness of Hiberix was measured by antibody titers produced after administration of the vaccine.4
- PedvaxHIB — According to the manufacturer’s product insert, the protective efficacy of PedvaxHIB measured during clinical trials of high-risk populations was estimated to be 93 to 100 percent, depending on the age of the child. A booster shot of PedvaxHIB is required in infants who complete the primary two-dose regimen before 12 months of age to maintain antibody levels.5
- Comvax — According to the manufacturer’s product insert, the protective efficacy of Comvax for Hib following the primary two-dose regimen in clinical trials was 93 percent. In the follow-up period post-clinical trials, the efficacy was 96.6 to 100 percent depending on the age of the child. Comvax’s total efficacy for HIB and hepatitis B was compared with the protective antibodies obtained from monovalent vaccines that showed adequate antibody responses of 72.4 to 100 percent depending on the population of children being studied and whether they had received prior doses of monovalent vaccines.6
- Pentacel — According to the manufacturer’s product insert, the protective efficacy of the pentavalent vaccine Pentacel may not extend to all individuals. If Pentacel is administered to immunocompromised persons, including those receiving immunosuppressive therapy, the expected immune response may not be obtained. Immunosuppressive therapies, including irradiation, antimetabolities, alkylating agents, cytotoxic drugs and corticosteroids used in greater than physiologic doses may also reduce the immune response to Pentacel. Neither the safety nor the effectiveness of Pentacel in infants less than 6 weeks old or in children ages 5 to 16 years old have been established.
In clinical studies with Pentacel, efficacy was measured by antibody responses to the individual five disease components contained in the vaccine. The efficacy against pertussis, which has no well-established serological correlate of protection, is based in part on a comparison of pertussis immune responses following Pentacel vaccine in U.S. children to responses following Daptacel vaccine (Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed―DTAP. Immune responses to Pentacel were evaluated in four U.S. studies.
The efficacy for diphtheria one month following three and four doses of Pentacel was 98 to 100 percent. Tetanus antibodies were reported at 99.7 to 100 percent. Pertussis efficacy was reported at 68.8 to 95.8 percent, depending on which study was being looked at. Protective antibodies against poliomyelitis with Pentacel in clinical trials were reported at 99.4 percent. Protection against invasive disease due to Hib was 90 to 98.2 percent depending on the study.7
- MenHibrix efficacy for Hib is evaluated by antibody levels of PRP measured in the blood and compared to similar vaccines containing H. influenza type b and then compared to other Hib-containing vaccines. According to the manufacturer, antibody levels for Hib efficacy were equal to other Hib vaccines. Antibodies to N. Meningitidis were reported at 95 percent and 98 percent during a clinical study. Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs, and corticosteroids may reduce the efficacy of this vaccine.8
IMPORTANT NOTE: NVIC encourages you to become fully informed about Haemophilus Influenza Type B (Hib) and the Hib 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.
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1 Todar K. Todar’s Online Textbook of Bacteriology. Haemophilus influenzae and Hib meningitis. 2008-2012. Online. (Accessed June 2012)
2 CDC.gov. Haemophilus Influenzae Type B. The Pink Book. No Date. Online. (Accessed June 2012)
3 FDA.gov. Haemophilus b Conjugate Vaccine ActHIB Manufacturer’s Product Insert. Sanofi Pasteur. May 6, 2009. Online. . (Accessed June 2012)
4 FDA.gov. Haemophilus b Conjugate Vaccine (Tetanus Toxoid Conjugate) Hiberix Manufacturer’s Product Insert. GlaxoSmithKline. No Date. Online. (Accessed June 2012)
5 FDA.gov. Haemophilus b Conjugate Vaccine (Meningococcal Protein Conjugate) Liquid Pedvax HIB. Merck & Co. 1998. Online. (Accessed June 2012)
6 FDA.gov. Haemophilus b Conjugate (Meningococcal Protein Conjugate) and Hepatitis B (Recombinant) Vaccine Comvax Product Insert. Merck & Co. 2001. Online. . (Accessed June 2012)
7 FDA.gov. Diphtheria and Tetanus Toxoids and Acellular Pertussis Adsorbed, Inactivated Poliovirus and Haemophilus b Congugate (Tetanus Toxoid Conjugate Vaccine) Pentacel. Sanofi Pasteur. July 2011. Online. . (Accessed June 2012)
8 FDA.gov. Menhibrix Manufacturer’s Product Insert. June 2012. Online. (Accessed June 2012)