KUALA LUMPUR, Jan 4 – A study on Covid-19 deaths in Malaysia found that unvaccinated individuals had a mortality rate 43.2 times higher than people fully vaccinated with Pfizer, and 12.5 times higher than people who obtained Sinovac.
The study by Nur Asheila Abdul Taib et al — which analysed Covid-19 deaths by vaccination types and status in the country between February and September 2021 — showed that the total Covid-19 age-standardised mortality rate (ASMR) was 47.5 per 100,000 population for the unvaccinated group. ASMR adjusts for differences in the age distribution of the population.
Among fully vaccinated individuals, the total Covid-19 ASMR of those who received Sinovac’s inactivated vaccine was 3.8 per 100,000 population, higher than recipients of Pfizer’s mRNA vaccine (1.1 per 100,000 population) and AstraZeneca’s viral vector vaccine.
According to the report, published in medical journal The Lancet Regional Health Western Pacific on January 1, 2022, people who received two Sinovac doses accounted for 58.7 per cent, or 3,577 Covid-19 deaths over the period, compared to 31.5 per cent or 1,919 Covid-19 deaths among double-vaccinated Pfizer recipients, and 582 (9.6 per cent) Covid-19 deaths among those who received two doses of AstraZeneca.
The study noted that AstraZeneca was first introduced through an opt-in programme due to initial safety concerns with the viral vector coronavirus vaccine.
“We opined that the recipients of the ChAdOx1 vaccine were likely to be younger and socioeconomically advantaged,” said researchers, referring to AstraZeneca. “Therefore, the outcome might be biased due to the populations’ lower risk of severe illness and death.”
Among those fully vaccinated with underlying health conditions, the mortality rate is 8.9 times, 4.1 times, and 1.5 times higher than those without comorbidities among recipients of Pfizer, Sinovac, and AstraZeneca, respectively.
For partially vaccinated individuals, those with underlying health issues similarly had a higher mortality rate than those without comorbidities across all vaccine types.
For partially vaccinated Pfizer recipients with comorbidities, the mortality rate is 3.6 times higher than those without comorbidities. Those partially vaccinated with Sinovac and AstraZeneca with comorbidities had a mortality rate of 2.4 times and 3.1 times higher, respectively, against those without comorbidities.
The report analysed a total of 20,823 Covid-19 deaths between February 24, 2021, and September 14, 2021. The median age of people who died of Covid-19 was 61 years.
Most deaths (4,946/ 20,823 or 24 per cent) occurred in the 60-69 age group. Male deaths outnumbered female deaths with a ratio of 1.33:1. More deaths occurred among Malaysians (87.5 per cent) and those with comorbidities (72.3 per cent).
“While we did not analyse immunological data in this study, the higher mortality rate among recipients of inactivated vaccines calls for close monitoring of breakthrough infections and deaths by vaccine types and further investigations into the recipients’ immunological profiles,” noted the study’s authors that included Dr Dhesi Baha Raja, Alvin Kuo Jing Teo, Dr Adeeba Kamarulzaman, Dr Timothy William, and Dr Arvinder-Singh HS.
“Evidence from Hong Kong indicated differing concentrations of neutralising antibodies between the inactivated (lower) and Pfizer vaccine recipients (higher), highlighting potential differences in vaccine effectiveness.
“Our study findings also concur with the recent recommendations by the World Health Organization (WHO) to offer a third dose to persons aged 60 and above who received inactivated vaccines.”
It further stated that vaccination coverage, monitoring breakthrough hospitalisations and deaths, safeguarding hospital capacity, and evidence-based booster strategy is critical to prevent Covid-19 mortality.
