The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya
<strong>Background</strong> 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....
| Main Authors: | , , , , , , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Journal article |
| Language: | English |
| Published: |
2021
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| _version_ | 1826308102501171200 |
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| author | Mburu, CN Ojal, J Chebet, R Akech, D Karia, B Tuju, J Sigilai, A Abbas, K Jit, M Funk, S Smits, G van Gageldonk, PGM van der Klis, FRM Tabu, C Nokes, DJ Scott, J Flasche, S Adetifa, I |
| author2 | LSHTM CMMID COVID-19 Working Group |
| author_facet | LSHTM CMMID COVID-19 Working Group Mburu, CN Ojal, J Chebet, R Akech, D Karia, B Tuju, J Sigilai, A Abbas, K Jit, M Funk, S Smits, G van Gageldonk, PGM van der Klis, FRM Tabu, C Nokes, DJ Scott, J Flasche, S Adetifa, I |
| author_sort | Mburu, CN |
| collection | OXFORD |
| description | <strong>Background</strong>
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.
<br>
<strong>Methods</strong>
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.
<br>
<strong>Results</strong>
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 ≥ 95% coverage in under-fives.
<br>
<strong>Conclusion</strong>
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. |
| first_indexed | 2024-03-07T07:14:28Z |
| format | Journal article |
| id | oxford-uuid:ddfb7fb3-1a4f-4ae0-bcaf-9a59449a8bff |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:14:28Z |
| publishDate | 2021 |
| record_format | dspace |
| spelling | oxford-uuid:ddfb7fb3-1a4f-4ae0-bcaf-9a59449a8bff2022-07-20T16:08:45ZThe importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in KenyaJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ddfb7fb3-1a4f-4ae0-bcaf-9a59449a8bffEnglishSymplectic Elements2021Mburu, CNOjal, JChebet, RAkech, DKaria, BTuju, JSigilai, AAbbas, KJit, MFunk, SSmits, Gvan Gageldonk, PGMvan der Klis, FRMTabu, CNokes, DJScott, JFlasche, SAdetifa, ILSHTM CMMID COVID-19 Working Group<strong>Background</strong> 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. <br> <strong>Methods</strong> 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. <br> <strong>Results</strong> 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 ≥ 95% coverage in under-fives. <br> <strong>Conclusion</strong> 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. |
| spellingShingle | Mburu, CN Ojal, J Chebet, R Akech, D Karia, B Tuju, J Sigilai, A Abbas, K Jit, M Funk, S Smits, G van Gageldonk, PGM van der Klis, FRM Tabu, C Nokes, DJ Scott, J Flasche, S Adetifa, I The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya |
| title | The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya |
| title_full | The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya |
| title_fullStr | The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya |
| title_full_unstemmed | The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya |
| title_short | The importance of supplementary immunisation activities to prevent measles outbreaks during the COVID-19 pandemic in Kenya |
| title_sort | importance of supplementary immunisation activities to prevent measles outbreaks during the covid 19 pandemic in kenya |
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