KUALA LUMPUR, Feb. 10 – A heterologous booster (primary Sinovac, followed by a Pfizer booster) provides better protection against infection than a homologous booster dose (three doses of Sinovac) in Sinovac recipients, according to Institute for Clinical Research (ICR), Ministry of Health (MOH).
While refuting Pharmaniaga Berhad’s claims of lesser efficacy of heterologous booster for recipients of Sinovac’s primary vaccination against Omicron, the ICR noted that the prevailing facts and evidence were distorted.
“Globally, there is emerging and consistent evidence that heterologous booster vaccination results in more robust immune responses and is more effective than homologous booster for recipients of the primary series of inactivated vaccines (Sinovac).
“Consistent with emerging evidence and the ongoing Omicron wave, the Department of Health continues to recommend Pfizer or AstraZeneca as the preferred booster for Sinovac vaccine recipients,” the ICR said in a statement today.
He said that in Malaysia, the Covid-19 vaccine effectiveness study under the Malaysian National Covid-19 Immunization Program Study used data from November 21, 2021 to January 7. 2022 to compare Covid-19 infection rates in recipients. booster doses and those who had only completed the primary vaccination.
“The analysis is based on real-world data, which included 13 million people who had received primary vaccination rounds from Pfizer and Sinovac.
“After controlling for confounders, those who just received booster doses were at least 90% less likely to be infected with Covid-19 than those who received only two doses,” he said. -he declares.
Citing a few studies conducted in various countries as examples, the ICR further explained the effectiveness of the heterologous booster for the Sinovac primary vaccination.
“In a study in Hong Kong SAR, a heterologous booster from Pfizer after two doses of Sinovac improved neutralizing antibody levels against the Omicron variant three to five weeks after the booster dose, but three doses of Sinovac failed to elicit neutralizing antibody responses to Omicron in most recipients.
“In another study conducted in Brazil, heterologous reinforcement (with AstraZeneca, Janssen and Pfizer) resulted in more robust immune responses than homologous reinforcement with the Sinovac booster, hence potentially stronger protection,” he said. he declares.
Meanwhile, he said in an interim statement on booster doses, the World Health Organization (WHO) has also noted that homologous and heterologous booster regimens are immunologically effective.
“A preprint of a study conducted in Chile observed an adjusted vaccine efficacy against symptomatic Covid-19 of 78.8% for three doses of Sinovac, 96.5% for the Pfizer booster (after two doses of Sinovac) and 93 .2% for the AstraZeneca booster (after two doses of Sinovac). — Bernama