Pharmaniaga Misrepresented Booster Jab Study Findings Ministry

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The Health Ministry has come forward to refute a recent statement by Pharmaniaga Berhad on the efficacy of the Sinovac-Sinovac-Pfizer regimen against the Covid-19 Omicron variant.
In a statement today, the ministry’s Institute of Clinical Research (ICR) noted that the government-linked company has “misrepresented” research findings.
“With reference to the media statement [...] by Pharmaniaga regarding the lower effectiveness of heterologous boosting for Sinovac primary vaccination recipients against Omicron, the ministry wishes to state that the prevailing facts and evidence are misrepresented.
“Globally, there is emerging and consistent evidence that heterologous booster vaccination results in more robust responses and is more effective than homologous boosting for recipients or primary series of inactivated vaccines (Sinovac),” it said.
The research in question refers to a Yale University study performed in the Dominican Republic that found that Sinovac-Sinovac-Pfizer offered “similar” protection as Pfizer-Pfizer against Omicron.
The study, which has yet to be peer-reviewed, found that Sinovac-Sinovac alone, sans any booster, was not able to neutralise Omicron. Sinovac-Sinovac recipients with prior Covid-19 infection were not able to neutralise Omicron either, it found.
The research did not compare these results against Sinovac-Sinovac-Sinovac recipients.
Yale University molecular, cellular and developmental biology professor Akiko Iwasaki posted a series of tweets about the findings back late last year, suggesting that Sinovac-Sinovac recipients may need “two additional booster doses” against Omicron.
In terms of public health, CoronaVac 2x is insufficient to neutralize Omicron. Even with CoronaVac 2x plus Pfizer booster, NAb is only 1.4x higher than 2x mRNA alone. Thus, CoronaVac recipients may need 2 additional booster doses to reach levels needed against Omicron. (10/) pic.twitter.com/fkTy9aL6eh
— Prof. Akiko Iwasaki (@VirusesImmunity) December 30, 2021Yesterday, Pharmaniaga interpreted the research to mean that a Sinovac-Sinovac-Pfizer regimen was “less effective” against Omicron.
It also cited laboratory research by China’s Sinovac Biotech Limited that found that a Sinovac-Sinovac-Sinovac regimen was effective against variants of concern “including Omicron”.
The GLC has a contract to distribute Sinovac vaccines in Malaysia.
mRNA boosters recommended
Aside from the Yale University study, the ICR cited laboratory studies from Hong Kong and Brazil, and a real-world study in Chile to contend heterologous boosters were more effective against Omicron than homologous boosters.
Malaysia’s own Recovam study also arrived at the same findings.
The latest analysis of the Recovam study compared infection rates among 13 million people between Nov 21 last year and Jan 7 this year who had previously received either the Pfizer or Sinovac vaccines. The timing coincides with the first cases of the Omicron variant in Malaysia, though the Delta variant is still circulating widely.
Those who had a Pfizer-Pfizer-Pfizer regimen were found to have 99 percent less risk of infection compared to just two doses of the Pfizer vaccine.
In comparison, those who had a Sinovac-Sinovac-Pfizer regiment had 94 percent risk reduction, and those who had three Sinovac doses had 92 percent risk reduction.
Meanwhile, those who only had two Sinovac doses were found to have an increased risk of infection compared to those who had two Pfizer doses, by 76 percent.
“Among Sinovac recipients, a heterologous booster (Sinovac-Sinovac-Pfizer) offered greater protection against infection than a homologous booster dose (Sinovac-Sinovac-Sinovac),” said the ICR.
“In line with emerging evidence and the ongoing Omicron wave, the ministry continues to recommend Pfizer or AstraZeneca as the preferred booster for Sinovac vaccine recipients,” it added.
It said studies in real-world settings are useful because vaccine performance cannot be predicted with high confidence from immune responses alone, as might be observed in laboratory studies.
This is because the correlates of protection against Covid-19 have not yet been defined. This refers to blood markers such as antibody and cellular immune responses that might be used to infer the degree of protection against a particular disease. - Mkini

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