What are the severe side effects of the Haemophilus influenzae type b (HIB) vaccine?

From the Guidelines

Severe side effects from the Haemophilus influenzae type b (Hib) vaccine are extremely rare, with serious adverse events occurring in fewer than 1 in a million doses, as reported in the most recent and highest quality study 1.

Overview of Side Effects

The most frequently reported adverse events after Hib vaccination include:

• Fever (31%)
• Crying (11%)
• Injection site erythema (11%)
• Irritability (10%)
• Rash (9%)

Serious Side Effects

Among the serious reports, the most frequent adverse events were:

• Fever (37%)
• Vomiting (21%)
• Convulsion (20%)
• Irritability (17%)
• Intussusception (11%)

Mortality

VAERS received reports of 878 deaths following Hib containing vaccines, with the most frequent cause of death being sudden infant death syndrome (52%) 1.

Recommendation

The benefits of the Hib vaccine in preventing potentially life-threatening infections far outweigh the minimal risk of serious side effects, and vaccination is recommended for all children under 5 years old, unless contraindicated due to a severe allergic reaction to any component of the vaccine 1. It is essential to note that the reporting frequencies for Hib containing vaccines are similar to what has been observed with other recommended childhood vaccines, and no unusual or unexpected safety patterns were observed in VAERS data for any Hib vaccines 1.

From the Research

Severe Side Effects of the Haemophilus influenzae type b (HIB) Vaccine

• The HIB vaccine has been found to have a very favorable safety profile 2
• No serious adverse reactions to Hib vaccine have been reported to date 3
• However, some adverse reactions have been reported, including:
  • Convulsions 4
  • Allergic reactions such as anaphylactoid-like and serum sickness-like reactions 4
  • Vomiting 4
  • Local and/or systemic reactions, such as redness, swelling, and fever 5
• It is worth noting that the vast majority of adverse reactions were benign 4
• Vaccine failure can occur, resulting in invasive Hib disease, even in vaccinated and immunocompetent children 6

Contraindications and Precautions

• The only specific contraindication is a history of severe local reaction or a general reaction to previous Hib vaccination 3
• The vaccine should be given by deep subcutaneous or intramuscular injection 3
• Routine immunisation of infants under 6 months of age against Hib has become part of the regular primary schedule in many countries 3