Estimating the herd immunity effect of rotavirus vaccine

Abstract

There is evidence that rotavirus vaccination confers a herd immunity effect in children under one year of age in the United States and Latin American countries. Given the high variability in vaccine efficacy across regions, more studies are needed to better examine herd immunity effects in high mortality regions.

Causes of Impaired Oral Vaccine Efficacy in Developing Countries

“…Binding to HBGA occurs through the VP8* domain of protein VP4 [76,77]. To date, 47 VP4 (P) genotypes have been identified, of which P [4], P [6] and P [8] are most common. A recent systematic review based on studies in France, Vietnam, the USA and Burkina Faso documented a 27-fold increase in susceptibility to P [8] rotavirus in secretors versus nonsecretors, but showed no association between secretor status and susceptibility to P [4] or P [6] genotypes [75].…”

“…To date, 47 VP4 (P) genotypes have been identified, of which P [4], P [6] and P [8] are most common. A recent systematic review based on studies in France, Vietnam, the USA and Burkina Faso documented a 27-fold increase in susceptibility to P [8] rotavirus in secretors versus nonsecretors, but showed no association between secretor status and susceptibility to P [4] or P [6] genotypes [75]. In Burkina Faso, no Lewis-negative secretors (expressing H type 1 antigen) were infected with P [8] strains, despite making up 25% of the study population [78], suggesting that the infectivity of P [8] strains may be dependent on both secretor and Lewis status.…”

“…Oral vaccines offer several distinct benefits compared with parenteral vaccines. They can be produced in large quantities at relatively low cost, are easy to administer and have the capacity to induce local immunity in the intestinal mucosa, thereby protecting vaccinated individuals against subsequent infection and -by blocking onward transmission -enhancing herd immunity [3,4]. Currently licensed oral vaccines include live-attenuated poliovirus vaccines containing one, two or three serotypes, live-attenuated rotavirus vaccines (Rotarix R , RotaTeq R , Lanzhou lamb rotavirus vaccine [China only] and Rotavac R [India only]), live-attenuated cholera vaccine (CVD 103-HgR or Vaxchora TM ), inactivated cholera vaccines (Dukoral R and Shanchol R ) and live-attenuated typhoid vaccine (Ty21a).…”

The Equity Impact Vaccines May Have On Averting Deaths And Medical Impoverishment In Developing Countries

“…This approach has limitations, such as not accounting for herd immunity (additional protective effect at the population level when a large percentage of population becomes immune) and dynamic transmissions (the changes in the nature of disease transmissions with varying numbers of people becoming susceptible, infected, and recovered over time). 32,33 In addition, nonspecific effects of vaccines, such as their effect on overall mortality, 34 as well as the timeliness of receiving the vaccines, 35,36 were not tak-…”

Vaccines are different: A systematic review of budget impact analyses of vaccines

“…Two of them were financially supported by the PCV13 producer [19,21] and the third study did not inform the funding, but one author had a grant from the PCV13 producer [20]. There is also evidence of herd protection with rotavirus vaccines [37] and out of four studies [16,22,25,30], two included herd protection in the analysis [16,22], one did not include it [30] and one did not mention it [25]. However, one must consider the evidence available at the time the studies were conducted.…”