Vaccine herd effect

Abstract

Vaccination ideally protects susceptible populations at high risk for complications of the infection. However, vaccines for these subgroups do not always provide sufficient effectiveness. The herd effect or herd immunity is an attractive way to extend vaccine benefits beyond the directly targeted population. It refers to the indirect protection of unvaccinated persons, whereby an increase in the prevalence of immunity by the vaccine prevents circulation of infectious agents in susceptible populations. The herd effect has had a major impact in the eradication of smallpox, has reduced transmission of pertussis, and protects against influenza and pneumococcal disease. A high uptake of vaccines is generally needed for success. In this paper we aim to provide an update review on the herd effect, focusing on the clinical benefit, by reviewing data for specific vaccines.

Postinfection A77-1726 Treatment Improves Cardiopulmonary Function in H1N1 Influenza-Infected Mice

“…However, rapid influenza virus mutation necessitates annual vaccine reformulation, and current limitations in the speed of vaccine production can prove problematic when novel influenza strains arise (4). Moreover, attitudes toward vaccination in the general population are by no means uniformly positive (5), and vaccination rates in the United States are consequently inadequate to control influenza transmission fully, particularly in high-risk populations (6). Furthermore, around 85% of developing countries have been estimated to have no access to vaccines during influenza pandemics (7).…”

24 year outcomes of hepatitis B vaccination in Hangzhou, China

“…Herd immunity induced by mass or nation-wide vaccination programs is well documented. [52][53][54] Preliminary studies have shown that lamivudine [55][56] and telbivudine 57 during pregnancy may reduce vertical transmission of HBV. Maternal to infant transmission may occur during the antenatal, intrapartum, or postnatal period.…”

Resurgence of pertussis calls for re-evaluation of pertussis animal models

“…Pertussis virtually disappeared in the industrialized world during the 1970s and 1980s, and herd immunity was initially observed [25]. Clearly, pertussis vaccination prevents severe illness and reduces infection-and transmission rates but not to the same extent as seen for other vaccine preventable childhood diseases [26,27]. In addition to reducing its incidence, 50-60 years of vaccination either with WCV and/or ACV profoundly changed the epidemiology of pertussis.…”