Waning COVID-19 Vaccine Effectiveness for BNT162b2 and CoronaVac in Malaysia: An Observational Study

Abstract

Evaluation of vaccine effectiveness over time against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or coronavirus disease 2019 (COVID-19) is important. Evidence on effectiveness over time for the CoronaVac vaccine is lacking despite its widespread use globally. In Malaysia, a diverse set-up of COVID-19 vaccines was rolled out nationwide, and the waning of vaccine protection is a concern. We aimed to investigate and compare waning vaccine effectiveness against COVID-19 infections, COVID-19 related ICU admission and COVID-19 related deaths for BNT162b2 and CoronaVac vaccines. In this observational study, we consolidated nationally representative data on COVID-19 vaccination and patients′ outcomes. Data on all confirmed COVID-19 cases from 1 to 30 September 2021 were used to compare vaccine effectiveness between the ′early′ group (fully vaccinated in April to June 2021) and the ′late′ group (fully vaccinated in Jul to Aug 2021). We used a negative binomial regression model to estimate vaccine effectiveness against COVID-19 infections for both ′early′ and ′late′ groups, by comparing the rates of infection for individuals vaccinated in the two different periods relative to the unvaccinated. Among confirmed COVID-19 cases, we used logistic regression to estimate and compare vaccine effectiveness against ICU admission and deaths between the two different periods. For BNT162b2, vaccine effectiveness against COVID-19 infections declined from 90.8% (95% CI 89.4, 92.0) in the late group to 79.1% (95% CI 75.8, 81.9) in the late group. Vaccine effectiveness for BNT162b2 against ICU admission and deaths were comparable between the two different periods. For CoronaVac, vaccine effectiveness waned against COVID-19 infections from 74.4% in the late group (95% CI 209 70.4, 77.8) to 30.0% (95% CI 18.4, 39.9) in the early group. It also declined significantly against ICU admission, dropping from 56.1% (95% CI 51.4, 60.2) to 29.9% (95% CI 13.9, 43.0). For deaths, however, CoronaVac′s effectiveness did not wane after three to five months of full vaccination. Vaccine effectiveness against COVID-19 infections waned after three to five months of full vaccination for both BNT162b2 and CoronaVac in Malaysia. Additionally, for CoronaVac, protection against ICU admission declined as well. Evidence on vaccine effectiveness over time informs evolving policy decisions on vaccination.

Vaccine effectiveness of one, two, and three doses of BNT162b2 and CoronaVac against COVID-19 in Hong Kong: a population-based observational study

“…29 However, the estimates presented are likely to be affected by time since vaccination, in that typically more time has passed since administration of second than third doses, which have only been widely available in Hong Kong since the beginning of Jan, 2022. Data from Malaysia 15 comparing the duration of protection of the BNT162b2 and CoronaVac vaccines show more rapid waning of protection following CoronaVac after two doses, in particular for mild and moderate outcomes. Furthermore, two-dose immunogenicity data from Hong Kong indicate lower humoral and cellular responses following CoronaVac than with BNT162b2 vaccination but whether inactivated vaccines given in three-dose schedules will provide similar protection to the mRNA vaccines in the long term is unclear.…”

“…Some observational evidence suggests strong and durable protection against severe disease and death from both vaccines, with transient protection against milder symptomatic disease. [14][15][16][17] With a largely infection-naive population and two COVID-19 vaccines in widespread use, Hong Kong represents a unique environment for monitoring vaccine effectiveness against omicron lineage BA.2. We aimed to estimate vaccine effectiveness of one, two, and three doses of BNT162b2 and CoronaVac, their relative effectiveness, and the additional protection offered by third doses against mild and moderate infections, severe disease, and death.…”

Vaccine effectiveness of two and three doses of BNT162b2 and CoronaVac against COVID-19 in Hong Kong

“…They find more rapid waning of CoronaVac, in particular for mild/moderate and severe outcomes, but to a lesser extent for COVID-19 related mortality. 23 Moreover, a recent study of humoral and cellular responses among Hong Kong vaccinees over time found that neutralising antibodies against variants of concern dropped to detection limit only three months after vaccinations, along with diminishing memory T cell responses, primarily among CoronaVac recipients. 36 Our study has a number of limitations arising from available data and the nature of the epidemic within Hong Kong.…”

“…21 Limited observational evidence suggests strong and durable protection against severe disease and death, with transient protection against milder symptomatic disease. [22][23][24][25] With a largely infection-naïve population and two COVID-19 vaccines in widespread use, Hong Kong represents a unique environment for monitoring vaccine effectiveness (VE) against Omicron BA.2. In this study we estimated VE of one, two and three doses of BNT162b2 and CoronaVac, their relative effectiveness, and the additional protection offered by third doses against mild/moderate infections, severe/fatal disease and death.…”

COVID-19 Vaccines—All You Want to Know

“…121 All the vaccines with longitudinal follow-up data have shown some degree of waning immunity with time through measured infections or decreased antibody levels ( Table 5 ). 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 Although there is certainly heterogeneity between studies, particularly regarding the degree of waning per vaccine, the general trend was captured in a systemic review and meta-regression of the BNT162b2, mRNA-1273, AZD1222, and Ad26.COV2.S vaccines. 131 The analysis suggests that vaccine effectiveness against symptomatic SARS-CoV-2 infection decreased on average 20 to 30 percent in 6 months after full vaccination.…”