Chemoprophylaxis of close contacts of invasive cases of haemophilus influenzae: a review

Background

Chemoprophylaxis to close contacts is recommended in case of invasive infection with Haemophilus influenzae serotype b (Hib). Since the introduction of generalized vaccination in 1993 in Belgium the number of invasive Hib infections decreased dramatically. Currently, the majority of invasive cases are caused by non-Hib strains. Considering these epidemiological changes, we wanted to find out if there are recent recommendations on antibiotic prophylaxis for invasive Hib infections and non-Hib infections.

Methods

We systematically searched PubMed and Embase for articles published from 2000 to 2023, using any combination of “Haemophilus influenzae”, “Haemophilus influenzae invasive”, “Haemophilus infections” or “bacterial meningitis” with “antibiotic prophylaxis”, “post exposure prophylaxis”, “secondary cases” or “communicable disease control”.

Additionally, we hand-searched relevant references cited by retrieved papers and used the abovementioned search terms in Google Scholar to identify research reports and government documents. We allowed inclusion articles published in English, French and Dutch. Finally, we looked for relevant references in the following standard works: the American Academy of Pediatrics (AAP) Red Book, the Plotkin’s vaccines and the Mandell’s Principles and Practice of Infectious Diseases.

Results

We found 5 articles, 5 regional/national guidelines (with one duplicate) and 3 mentions in reference books. We excluded 1 article because of lack of specificity (no difference between meningococcus and Hib chemoprophylaxis). We did not find any changes since 2000 regarding chemoprophylaxis for close contact of an invasive case of Hib. Regarding non-Hib strains, the Red Book recommends to consider chemoprophylaxis in case of H. influenzae serotype a (Hia) for household contacts and pre-school and child care under certain conditions. This recommendation is based on evidence of secondary cases with Hia especially in some North American Indigenous populations. Based on the same evidence, Ulanova et al. in 2014 concluded that chemoprophylaxis might prevent secondary Hia infections, although no data are available for drug choice, dosage, and effectiveness in prevention of development of disease and carriage.

Conclusion

The AAP recommends to consider antibioprophylaxis for HIa, but this recommendation is based on limited evidence in a specific population and not included in guidance of the CDC nor any other organisation we could identify.