A study by Chinese experts now shows that the production of antibodies from Sinovac COVID-19 vaccines decreases over six months, so it is necessary to have a third injection as a ‘booster shot.’
The study included blood samples of 50 healthy adults aged 18-59 years. The study results have been published in China but have not yet been subjected to peer review.
Of the participants who received 2 doses of Sinovac vaccine with a 2-4 week interval, only 16.9% and 35.2% of them had detected antibodies after six months.
It is not clear how the decrease in antibodies will affect the vaccine’s effectiveness because scientists have not yet determined the level of antibodies to fight the coronavirus.
About 540 participants were given the third dose of the vaccine six months after the second dose. Here an increase of up to 5 times the antibody count was seen after 28 days compared to those given only two shots of the vaccine.
Health Secretary Francisco Duque III clarified that the vaccine expert panel has not yet recommended giving a booster shot to Sinovac patients.
3rd dose of Sinovac vaccine possible – study
The FDA said that Sinovac vaccine’s efficacy is from 65.3% to 91.2%. However, it only reached 50.4% among health workers with COVID-19 exposure.
“This should be administered by vaccination providers and to prevent COVID-19 in clinically healthy individuals aged 18 to 59 years old,” FDA chief Eric Domingo said.
“The use of Sinovac COVID-19 vaccine on health care workers is not recommended as it has an efficacy rate of 50.4% in this group,” he added.
Doming said the Sinovac vaccine is not the best option for health care workers, citing the trials conducted in Brazil.
However, the FDA chief said the Sinovac COVID-19 vaccine’s side effects are only under mild to moderate categories.
“Iyong safety profile niya, iyong adverse effects, usual lang na pananakit sa vaccination area, kaunting sinat. Pero sa allergy/anaphylaxis (difficulty in breathing) analysis, mababa ang posibilidad ng mga ito sa bakunang ito,” Domingo said.
Meanwhile, Presidential spokesperson Harry Roque maintained that Sinovac is not a sub-par vaccine and could be used for health care workers.
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