학술논문

The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya
Document Type
Report
Source
BMC Medicine. February 3, 2021, Vol. 19 Issue 1
Subject
Kenya
Language
English
ISSN
1741-7015
Abstract
Background The COVID-19 pandemic has disrupted routine measles immunisation and supplementary immunisation activities (SIAs) in most countries including Kenya. We assessed the risk of measles outbreaks during the pandemic in Kenya as a case study for the African Region. Methods Combining measles serological data, local contact patterns, and vaccination coverage into a cohort model, we predicted the age-adjusted population immunity in Kenya and estimated the probability of outbreaks when contact-reducing COVID-19 interventions are lifted. We considered various scenarios for reduced measles vaccination coverage from April 2020. Results In February 2020, when a scheduled SIA was postponed, population immunity was close to the herd immunity threshold and the probability of a large outbreak was 34% (8-54). As the COVID-19 contact restrictions are nearly fully eased, from December 2020, the probability of a large measles outbreak will increase to 38% (19-54), 46% (30-59), and 54% (43-64) assuming a 15%, 50%, and 100% reduction in measles vaccination coverage. By December 2021, this risk increases further to 43% (25-56), 54% (43-63), and 67% (59-72) for the same coverage scenarios respectively. However, the increased risk of a measles outbreak following the lifting of all restrictions can be overcome by conducting a SIA with [greater than or equai to] 95% coverage in under-fives. Conclusion While contact restrictions sufficient for SAR-CoV-2 control temporarily reduce measles transmissibility and the risk of an outbreak from a measles immunity gap, this risk rises rapidly once these restrictions are lifted. Implementing delayed SIAs will be critical for prevention of measles outbreaks given the roll-back of contact restrictions in Kenya. Keywords: Measles, Vaccination coverage, Outbreak, COVID-19, Supplementary immunisation activities
Author(s): C. N. Mburu[sup.1,2] , J. Ojal[sup.1,2] , R. Chebet[sup.1] , D. Akech[sup.1] , B. Karia[sup.1] , J. Tuju[sup.1] , A. Sigilai[sup.1] , K. Abbas[sup.2] , M. Jit[sup.2] , S. [...]