The importance of increasing primary vaccinations against COVID-19 in Europe
In the European Union, mass vaccination against COVID-19 staved off the strict restrictions that had characterized early epidemic response. Now, vaccination campaigns are focusing on booster doses, and primary vaccinations have all but halted. Still, 52 million European adults are unvaccinated.We in...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2024-03-01
|
| Series: | Infectious Disease Modelling |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2468042723000982 |
| _version_ | 1797317150847795200 |
|---|---|
| author | Pierre-Yves Boëlle Eugenio Valdano |
| author_facet | Pierre-Yves Boëlle Eugenio Valdano |
| author_sort | Pierre-Yves Boëlle |
| collection | DOAJ |
| description | In the European Union, mass vaccination against COVID-19 staved off the strict restrictions that had characterized early epidemic response. Now, vaccination campaigns are focusing on booster doses, and primary vaccinations have all but halted. Still, 52 million European adults are unvaccinated.We investigated if reaching the still unvaccinated population in future vaccination campaigns would substantially decrease the current burden of COVID-19, which is substantial. We focused on vaccination homophily, whereby those who are unvaccinated are mostly in contact with other unvaccinated, making COVID-19 circulation easier. We quantified vaccination homophily and estimated its impact on COVID-19 circulation.We used an online survey of 1,055,286 people from 22 European countries during early 2022. We computed vaccination homophily as the association between reported vaccination status and perceived vaccination uptake among one's own social contacts, using a case-referent design and a hierarchical logistic model. We used this information in an analysis of the COVID-19 reproduction ratio to determine the impact of vaccine homophily in transmission.Vaccination homophily was present and strong everywhere: the average odds ratio of being vaccinated for a 10-percentage-point increase in coverage among contacts was 1.66 (95% CI=(1.60, 1.72)). Homophily was positively associated with the strictness of COVID-19-related restrictions in 2020 (Pearson = 0.49, P = .03). In the countries studied, 12%-to-18% of the reproduction ratio would be attributable to vaccine homophily.Reducing vaccination homophily may curb the reproduction ratio substantially even to the point of preventing recurrent epidemic waves. In addition to boosting those already vaccinated, increasing primary vaccination should remain a high priority in future vaccination campaigns, to reduce vaccination homophily: this combined strategy may decrease COVID-19 burden. |
| first_indexed | 2024-03-08T03:29:44Z |
| format | Article |
| id | doaj.art-d71513d455f34df7906101c48edd55ed |
| institution | Directory Open Access Journal |
| issn | 2468-0427 |
| language | English |
| last_indexed | 2024-03-08T03:29:44Z |
| publishDate | 2024-03-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Infectious Disease Modelling |
| spelling | doaj.art-d71513d455f34df7906101c48edd55ed2024-02-11T05:11:39ZengKeAi Communications Co., Ltd.Infectious Disease Modelling2468-04272024-03-019119The importance of increasing primary vaccinations against COVID-19 in EuropePierre-Yves Boëlle0Eugenio Valdano1Sorbonne Université, INSERM, Institut Pierre Louis d’Epidémiologie et de Santé Publique, F75012, Paris, FranceCorresponding author. Institut Pierre Louis d’Epidémiologie et de Santé Publique, INSERM & Sorbonne Université, site Hôpital St. Antoine, 27 rue Chaligny, 75012, Paris, France.; Sorbonne Université, INSERM, Institut Pierre Louis d’Epidémiologie et de Santé Publique, F75012, Paris, FranceIn the European Union, mass vaccination against COVID-19 staved off the strict restrictions that had characterized early epidemic response. Now, vaccination campaigns are focusing on booster doses, and primary vaccinations have all but halted. Still, 52 million European adults are unvaccinated.We investigated if reaching the still unvaccinated population in future vaccination campaigns would substantially decrease the current burden of COVID-19, which is substantial. We focused on vaccination homophily, whereby those who are unvaccinated are mostly in contact with other unvaccinated, making COVID-19 circulation easier. We quantified vaccination homophily and estimated its impact on COVID-19 circulation.We used an online survey of 1,055,286 people from 22 European countries during early 2022. We computed vaccination homophily as the association between reported vaccination status and perceived vaccination uptake among one's own social contacts, using a case-referent design and a hierarchical logistic model. We used this information in an analysis of the COVID-19 reproduction ratio to determine the impact of vaccine homophily in transmission.Vaccination homophily was present and strong everywhere: the average odds ratio of being vaccinated for a 10-percentage-point increase in coverage among contacts was 1.66 (95% CI=(1.60, 1.72)). Homophily was positively associated with the strictness of COVID-19-related restrictions in 2020 (Pearson = 0.49, P = .03). In the countries studied, 12%-to-18% of the reproduction ratio would be attributable to vaccine homophily.Reducing vaccination homophily may curb the reproduction ratio substantially even to the point of preventing recurrent epidemic waves. In addition to boosting those already vaccinated, increasing primary vaccination should remain a high priority in future vaccination campaigns, to reduce vaccination homophily: this combined strategy may decrease COVID-19 burden.http://www.sciencedirect.com/science/article/pii/S2468042723000982COVID-19Vaccination campaignReproduction ratioVaccination homophilySurveyEurope |
| spellingShingle | Pierre-Yves Boëlle Eugenio Valdano The importance of increasing primary vaccinations against COVID-19 in Europe Infectious Disease Modelling COVID-19 Vaccination campaign Reproduction ratio Vaccination homophily Survey Europe |
| title | The importance of increasing primary vaccinations against COVID-19 in Europe |
| title_full | The importance of increasing primary vaccinations against COVID-19 in Europe |
| title_fullStr | The importance of increasing primary vaccinations against COVID-19 in Europe |
| title_full_unstemmed | The importance of increasing primary vaccinations against COVID-19 in Europe |
| title_short | The importance of increasing primary vaccinations against COVID-19 in Europe |
| title_sort | importance of increasing primary vaccinations against covid 19 in europe |
| topic | COVID-19 Vaccination campaign Reproduction ratio Vaccination homophily Survey Europe |
| url | http://www.sciencedirect.com/science/article/pii/S2468042723000982 |
| work_keys_str_mv | AT pierreyvesboelle theimportanceofincreasingprimaryvaccinationsagainstcovid19ineurope AT eugeniovaldano theimportanceofincreasingprimaryvaccinationsagainstcovid19ineurope AT pierreyvesboelle importanceofincreasingprimaryvaccinationsagainstcovid19ineurope AT eugeniovaldano importanceofincreasingprimaryvaccinationsagainstcovid19ineurope |