https://www.thestar.com.my/news/nation/2022/01/16/get-jabbed-sinovac-recipients-told

PETALING JAYA: Almost everyone who has had both doses of the Sinovac Covid-19 vaccine is eligible for the booster shot and should not delay getting it, say health experts.

Allaying concerns over mixed vaccines, particularly among those who had received the Sinovac vaccine, the experts assured the public that heterologous booster shots are safe and effective.

According to CovidNow, most Sinovac doses were administered between June and August last year, indicating that most adults fully vaccinated with Sinovac should be eligible for their third shot. However, many are not coming forward or keeping their appointments.

Universiti Sains Malaysia virology scientist Dr Muhammad Amir Yunus said the booster shots are aimed at topping up the neutralising antibody levels.

“Based on scientific evidence, Sinovac’s efficacy is relatively lower compared to others.

“The efficacy of Sinovac against new variants, especially Omicron, might be lower and therefore, opting for a higher efficacy booster shot is good.

“People who do not have underlying health problems and could receive a different brand of vaccine such as Pfizer should go for it as heterologous booster shots are proven to be effective and safe,” he said.

Dr Muhammad explained that the Sinovac vaccine is based on whole inactivated virions.

“Multiple antigenic parts of the virus can stimulate immune responses with different antibodies.

“However, sometimes the relatively lower concentration of these antigenic parts in the Sinovac’s prep – due to the inactivation process which can destroy these antigenic parts – might contribute to the poorer efficiency of the vaccine to stimulate immune response.

“In Pfizer’s vaccine, which targets the specific part of the virus’ antigen, the preps contain only a transcript copy of information that will be used by our cells to produce only intact spikes in antigen levels.

“This can induce a more specific antibody at higher levels which contribute to a better efficacy,” he said.

Universiti Putra Malaysia medical epidemiologist Assoc Prof Dr Malina Osman also gave a reassurance that all Covid-19 vaccines are effective to induce antibody production.

“Regardless of the technology used to produce the vaccines, all are meant to prevent infection and possible severe complications.

“The public should not worry if given a vaccine which is not the same as the previous two doses.

“Heterologous vaccines have also shown higher production of antibodies and also have low probability of adverse side effects,” she said.

Dr Malina added that as the pandemic situation in our country is still under threat of a possible new surge of cases due to Omicron, the booster doses are urgently needed.

“Booster doses in Sarawak have proven their effectiveness in preventing possible new clusters after the recent state election.

“Even with the recent flood disasters, the administration of booster doses among the high-risk groups which started in November helped to maintain the number of active cases below 40,000.

“I hope all individuals who are eligible to receive vaccines and are given appointments come forward as advised,” she said.

Datuk Dr Zainal Ariffin Omar, who heads volunteers for community engagement and empowerment for Covid-19, said it is important that people get their booster shot as soon as possible because the immunity is waning while new variants are emerging.

“Studies have shown that both Pfizer-Astrazeneca is one of the best combinations as booster shots.

“I urge those who have received Sinovac vaccines not to hesitate in taking Pfizer or AZ as their booster shots,” Dr Zainal said.

As at Jan 15, a total of 25,674,070 adults have been fully vaccinated but only 9,043,384 have received their booster shots, which is around 35%.

Meanwhile, ProtectHealth Corporation chief executive officer Datuk Dr Anas Alam Faizli said more vaccination centres (PPV) are open now to increase accessibility to the public.

“Based on this increase in PPV capacity and positive feedback from vaccine recipients, it is targeted that 60% of adults would have received booster doses by the end of January and 80% by the end of February,” he said.

“We are seeing positive feedback from vaccinees on both homologous and heterologous vaccination as both are effective and safe.”

To date, there are 1,915 general practitioner PPVs, 111 private hospital PPVs and 150 offsite PPVs that are operating under ProtectHealth on top of the 760 PPVs by the government.

- Source from The Star Online