11 July 2024

Though more than 2.8 million people in Thailand have already received their fourth jab against COVID-19, many others are still skeptical about what good a “second booster” can do.

The World Health Organisation (WHO) has yet to recommend the fourth dose, citing a lack of good evidence to back the recommendation. Hence, countries have taken different approaches where the second booster is concerned.

In Thailand, the government is encouraging people to get the fourth jab and has opened several channels for them to get their shot for free.

Leading Thai virologist Dr. Yong Poovorawan is advising people in high-risk groups, namely those aged over 50 and those with chronic illnesses like kidney disease or cancer, to get a fourth shot.

“Another high-risk group is medical personnel. They should also get a fourth jab,” he said.

When is the best time?

Different institutes have issued slightly different guidelines for when to get a fourth jab. However, the one thing most of them agree upon is that people who have received inactivated vaccines like Sinovac or Sinopharm should get their fourth jab at least three months after their third shot.

Those who have received a viral vector vaccine like AstraZeneca are advised to take the fourth shot four months after the third jab.

The Central Vaccination Centre at Bang Sue Grand Station also automatically schedules the fourth shot for people who have taken their previous jabs at the center.

Those who have received their third shot elsewhere are also welcome to schedule their fourth shot via their mobile providers.

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What’s so good about a 4th shot?

Ashley St John, an associate professor at Duke-NUS Medical School in Singapore, said the second booster helps stop COVID infections from becoming severe.

“This booster’s effect is the strongest shortly after the vaccine is administered and provides overall protection,” she said.

Singapore, as well as Israel and Denmark, has been offering the fourth shot to its people in a bid to minimize COVID-19 casualties.

Official records show the virus has killed more than 6.25 million people across the world since the pandemic began over two years ago. Earlier this month, WHO said the total death toll associated directly or indirectly with COVID-19 (“excess mortality”) between January 1, 2020, and December 31, 2021, stood at about 14.9 million, with a range of 13.3 million to 16.6 million.

In Thailand, more than 29,000 people have succumbed to COVID-19 to date. More than 90 percent of the deaths in the past three months were of unvaccinated people.

Doubts about fourth dose

Some medical experts say the fourth dose may not help much because the immunity it offers drops so quickly. The emergence of several variants has also cast doubt on the efficacy of vaccines currently available.

“If the virus changes so much that you need to change your vaccine composition, then you won’t need another shot,” WHO chief scientist Soumya Swaminathan said in an interview with CNBC.

Several countries, meanwhile, are only offering the fourth jab to vulnerable groups. The United States, for instance, has authorized a fourth shot only for those above the age of 50 and those with compromised immunity.

The European Centre for Disease Prevention and Control and the European Medicines Agency’s COVID-19 task force have concluded that it is too early to consider using the fourth dose of mRNA COVID-19 vaccines (Pfizer’s Comirnaty and Moderna’s Spikevax) in the general population.

However, both agencies agree that a fourth dose should be given to the elderly, after reviewing data on the higher risk of severe COVID-19 infections in this age group and the protection that can be provided by a fourth shot.

By Thai PBS World’s General Desk