PharmacoEconomics & Outcomes News 792, p10 - 2 Dec 2017
Economic studies of vaccines use
static model of herd immunity
Most economic studies of vaccines use static models
for estimating herd immunity, according to findings of a
systematic review of the methodology used which was
published in Vaccine.
Investigators used data from a previous systematic
review of models used in cost-effectiveness evaluations
of vaccines between 1976 and 2007, and searched
PubMed/MEDLINE and Embase databases for similar
evaluations published between 2007 and 2015.
Of 625 economic evaluations which met the selection
criteria, 172 included herd immunity. Herd immunity
was included in 53% of studies published in 2015
compared with only 4% of studies published in 2001,
and was considered in 63% of evaluations of human
papillomavirus vaccines, pneumococcal vaccines and
Only 59 of the studies which considered herd
immunity used a dynamic model; 95 studies used a
static model and eight used a hybrid model The method
of modelling was not clearly stated in ten studies.
Most of the studies which used a static model used
"relatively crude methods and assumptions," said the
investigators. "Values from a static model can only be
considered reliable if high quality surveillance data are
incorporated into the analysis. Without this, the results
are questionable and they should only be included in
sensitivity analysis," they commented.
Nymark LS, et al. Inclusion of the value of herd immunity in economic evaluations
of vaccines. A systematic review of methods used. Vaccine : 13 Nov 2017.
Available from: URL: http://doi.org/10.1016/j.vaccine.2017.10.024
PharmacoEconomics & Outcomes News 2 Dec 2017 No. 7921173-5503/17/0792-0001/$14.95 Adis © 2017 Springer International Publishing AG. All rights reserved