A WARNING ON WANING: THE DURATION OF VACCINE-DERIVED IMMUNITY IN MALAYSIA

Abstract

Intro: Vaccinations have decreased the case fatality rate of COVID-19. Nonetheless, there appear to be differences in the duration of vaccine efficacy against death across populations.We aim to model the duration between vaccine type and time to death stratified by primary and booster series vaccination in Malaysia. Methods: Data for all COVID-19 deaths between 1 February 2020 and 31 August 2022 were extracted from the Ministry of Health Malaysia data repository. Information was available on age, sex, nationality, region, vaccine status, vaccine type, and the duration from vaccination to death. The duration between primary or booster vaccination and death was modelled using Poisson regression. Findings: A total of 25,759 (77%), 7,421 (20%), and 1,036 (2.9%) unvaccinated, primary series vaccinated, and booster vaccinated COVID-19 deaths were respectively reported between 1 February 2020-31 August 2022 in Malaysia. The median duration between primary series vaccination and death, with AstraZeneca, Pfizer and Sinovac vaccines was respectively 150 (IQR: 73-211), 158 (IQR:88-229) and 105 (65-139) days. The median duration between booster vaccine and death with a Homologous or Heterologous vaccine was 86 (IQR: 59- 139) and 106 (66-139) days, respectively. Individuals with an AstraZeneca and Sinovac primary series had 19% (95% CI: 0.8-0.82) and 33% (95% CI: 66-0.68, p<0.01) shorter duration from vaccination to death than individuals with Pfizer vaccines. Individuals with a heterologous booster vaccination had an 8% (95% CI: 1.07-1.10, p<0.01) longer duration from vaccination to death than individuals receiving a homologous booster dose. Conclusion: There appear to be differences in the duration between vaccination and death by vaccine type. This must be considered alongside immune evasive variants and level of naturally acquired immunity when planning for vaccination programmes that are central to keeping COVID-19-associated mortalities low.