Protection could last up to 18 months

Individuals vaccinated against Covid-19 may be protected for up to 18 months.

Beyond that, additional vaccination shots might be needed if a person's immunity to the virus begins to wane, the Ministry of Health's (MOH) director of medical services Kenneth Mak said yesterday.

Another jab could also be required to guard against new variants of the coronavirus, he added in response to a question at a virtual news conference on plans to administer a third dose of the vaccine.

Associate Professor Mak said: "At this point in time, there is quite a bit of thought that the vaccinations should be able to last us for at least nine months to 12 months.

"We believe that it is going to be much longer than that, perhaps even 15 to 18 months. But beyond that, it is still a relatively uncertain situation."

Prof Mak said the immunity accorded by the vaccines could wane, just like how recovered patients have gradually reduced protection against the virus.

The authorities will conduct follow-up tests on some of the people who have been fully vaccinated, he said, adding: "If we find that their immune levels start to drift downwards, it would then be the right time to start planning to vaccinate these people as well."

He also noted that while the Pfizer-BioNTech and Moderna vaccines are effective in protecting against current Covid-19 variants, Singapore has to prepare for the possibility that they may not be as effective against future variants.

"If that were the case, it may well be the case that we need booster vaccine doses to augment the immunity that we already have from the previous vaccinations and to give us additional protection, particularly against these variants of concern," he added.

Singapore is studying the issue and has discussed it with other countries, said Prof Mak.

The vaccine manufacturers are looking into it as well, he added, and hope to produce vaccines to guard against new variants of the coronavirus.

"Where such a product is available, we may plan to make that available as booster doses in the population that had previously been vaccinated," said Prof Mak.

As at April 18, more than 2.2 million doses of Covid-19 vaccines have been administered in Singapore. Almost 850,000 people have received both doses.

Health Minister Gan Kim Yong said yesterday that the Republic continues to make steady progress in its vaccination programme.

Thirty-eight vaccination centres have been set up, on top of 20 polyclinics and 22 Public Health Preparedness Clinics offering jabs.

Two other vaccination centres will be set up by this week.

Mr Gan said he was encouraged by the response of Singaporeans to the vaccination programme.

"However, our supply remains limited, given the global shortage," he noted.

"I therefore encourage all medically eligible Singaporeans and long-term residents to go for vaccination when it is offered to you."