Get your boosters! Old Covid-19 vaccines work just fine, says DDC


The Covid-19 vaccines currently available are good enough to boost people’s immunity, the Department of Disease Control (DDC) has said.

DDC director-general Dr Tares Krassanaiwiwong said on Friday that though the Covid-19 situation is easing in Thailand, there are still waves of infections.

So far, 95% of the Covid-related deaths fall in the 608 group, namely people aged 60 and above, those with chronic diseases, pregnant women and those over 90 kilos in weight, as well as the unvaccinated or those who did not receive a booster shot for more than three months.

Hence, the DDC’s sub-committee on promoting disease immunity on December 9 resolved to have targeted groups given a booster shot from the vaccines currently available instead of having them wait for the newer mRNA bivalent vaccines.

Tares said the mRNA monovalent vaccines are still effective against the current virus strain and will reduce the severity of symptoms.

He also rejected the study claiming that taking more than three booster shots will not improve immunity or prevent infection.

Citing figures in Thailand, he said taking a fourth jab cuts down the development of severe symptoms and deaths far better.

He also said most of the deaths from Covid were among the unvaccinated or those who had received a jab a long time ago.

Hence, Tares said, the Public Health Ministry’s aim is to provide booster shots to those who got their third dose more than four months ago.

Meanwhile, expert virologist Dr Yong Poovorawan talked about a study conducted in the US from September to November, in which an mRNA bivalent booster was administered to people who had received at least two doses of mRNA monovalent vaccines.

The study shows that the vaccine can reduce the rate of infection by 28 to 56%, while the immunity provided is no different than the monovalent vaccines.

He also cited the World Health Organisation (WHO)’s statement on October 17, which said that both the current and new mRNA vaccines can be used as a booster dose.

Yong added that everybody should get at least four vaccines to protect themselves, especially those in the at-risk group who had taken their last jab more than four months ago.

Dr Sophon Iamsirithaworn, DDC deputy director-general, said the currently available vaccines are efficient enough to prevent the disease and reduce the severity of symptoms much like newer vaccines.

The Public Health Ministry, meanwhile, is monitoring the situation and updating suggestions in line with the current situation.

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