SINGAPORE - New variants of the virus that causes Covid-19 have recently caused some concern that they may evade the immune response induced by existing vaccines, but there is no evidence yet of this occurring, said experts here, urging people not to hesitate over getting vaccinated.

"Existing vaccines work against the virus variants circulating in the community, so people should continue to step up to receive the vaccine," said Professor Benjamin Seet, deputy group chief executive for education and research at the National Healthcare Group and a member of the expert committee on Covid-19 vaccination.

"The more people who are vaccinated, the more who will be protected against current variants and, likely, new variants as well."

Sars-CoV-2, the virus that causes Covid-19, began mutating soon after it was discovered. The new variants that were first identified in Britain (B117), Brazil (P1) and South Africa (B1351) appear to be more contagious. In pre-emptive moves, vaccine developers are preparing to modify their vaccines against these variants.

"There is no immediate cause for concern, as these new variants have not been shown to cause more serious illness," said Prof Seet, who chairs an expert panel that looks at the science and technical aspects of Covid vaccines to determine which ones are better.

"If the virus continues to mutate, there may be a need for second-generation vaccines or a booster. But it is really too early to tell."

For now, existing vaccines are not affected but many people remain hesitant about taking them.

"Quite a number of people have asked me about the speed of development of the vaccines, and they are concerned that what normally takes five to 10 years is now compressed into a matter of months," said Prof Seet.

But the unprecedented spread of the disease has led to an unprecedented response.

"For a typical infectious disease, we'll be lucky to have a handful of companies trying to make a vaccine for it. What's happening now is that there are more than 200 efforts globally," said Prof Seet.

The amount of funds that has poured into Covid-19 vaccine development is also "totally unprecedented in history".

Associate Professor Lim Poh Lian, who is also a member of the expert committee on Covid-19 vaccination, noted that "governments around the world were providing funding to the pharmaceutical companies to reduce some of that commercial risk because if you make three movies all at one shot, and they all bomb, then you've just lost three times as much money".

Clinical trials could also be sped up because of the widespread outbreaks in many countries.

Prof Lim said: "With Covid-19, there were enough people willing to volunteer because they could see the pandemic happening.

"And it was actually gaining transmission in the community, so you can see whether the vaccine works or not."

Changes in the regulatory review process also helped.

Traditionally, vaccine companies would submit a vaccine for review only when all the data is in, but they are now providing their data to the authorities on a rolling basis, as it comes in.

Prof Seet said that the groundwork to get Covid-19 vaccines into Singapore started last April, when experts started looking at "seven or eight different types of vaccine technologies".

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