In a live interview with Editor in Chief of TOC Terry Xu on Saturday (15 May), Prof Paul Ananth Tambyah—who is a Senior Consultant, Division of Infectious Diseases, Department of Medicine, National University Hospital —said that it doesn’t appear that the vaccines are “ineffective” against the new variants of COVID-19.
Citing the United Kingdom’s “aggressive vaccination programme”, Prof Tambyah said that has likely contributed to the significant drop in the number of daily COVID-19 cases there.
He went on, “You know, people always ask me, how come the vaccinated nurse in TTSH got infected? I told them, ‘Do you know that there are about 30 to 40 nurses working in a C-class ward in Singapore? The fact that only one nurse got infected shows that the vaccine is pretty effective.”
In contrast, around 15 to 20 nurses were infected during the SARS outbreak due to a lack of vaccines, he noted. Prof Tambyah stressed that only two vaccinated patients were infected, whereas the unvaccinated patients had a very high infection rate.
He went on to explain that the research shows that the Pfizer-BioNTech and Moderna vaccines work about 95 per cent of the time, meaning that only one in 20 people who are exposed to the virus post-vaccination are going to get sick, and if they do get sick, they will not become severely ill.
“So I still think that the vaccines are going to work,” he exclaimed.
As to why some people can be reinfected with the virus despite being vaccinated, Prof Tambyah said that it is less than 1 per cent of vaccinated people who are reinfected. He stressed that this is likely to happen in people with weakened immune systems, adding that reinfection for them could result in severe illness.
However, the majority of reinfected persons only experience a mild illness, said Prof Tambyah, pointing to the example of migrant workers in the Westlite Dormitories who had been found to be reinfected.
Prof Tambyah noted that while there may be some genetic reason why some people are prone to reinfections, the number is very small.
He explained, “Like the flu, this coronavirus also changes but it doesn’t change as fast, and it has intrinsic characteristics with make it less likely to mutate like the flu.”
Vaccinations will have huge implications on future strategies against COVID
As such, when asked what effect vaccination efforts may have in combating the virus given that most people who have it are asymptomatic, Prof Tambyah noted that conclusions are based on clinical trial data.
“When you’re in a clinical trial, they collect data very, very rigorously… and based on the clinical trial data, as I said, there is about a 5 per cent failure rate for the vaccine,” adding that those 5 per cent tended to have mild diseases, meaning no hospitalisation, ICU care and fewer deaths.
“This has got huge implications for the strategies moving forward,” noted Prof Tambyah.
He explained that if a significant portion of the population is vaccinated, about 80 to 90 per cent, as opposed to the oft-quoted 70 per cent, the spread of the virus within Singapore, could be mitigated.
Noting Singapore’s global connection and dependence on migrant workers, Prof Tambyah said: “If a significant portion of the population is immunised, then you’re not going to get a severe disease. So this should be the goal. Zero deaths, zero severe infections, rather than zero COVID.”
Not everyone will need a third booster
On the issue of possibly taking a third booster shot of the vaccine, as eluded to by then-Health Minister Gan Kim Yong, Prof Tambyah said that very few viral infections require a third booster.
“The exception is the flu where you need to get vaccinated every year. That’s because the virus mutates,” he added.
Noting how every commercially available vaccine is 90 to 95 per cent effective, there is about 5 to 10 per cent of people who “are not going to have a good response.”
Therefore, Prof Tambyah added that perhaps those at high risk or those working in high-risk areas such as Changi Airport or the harbour could benefit from a booster. The caveat here is that it is now possible to measure the antibody levels in these people to see how protected they are from the virus.
“So some individuals, we may need to give a third booster, but I certainly don’t think that’s going to be the case for everyone,” he emphasised.