SINGAPORE – Protection against severe forms of Covid-19, whether through vaccination or illness as a result of the virus, wanes around the 12-month mark, and those most at risk must take their annual vaccine shots to avoid getting severely ill, said Health Minister Ong Ye Kung on Friday.

Mr Ong’s warning was timely, as Singapore is currently going through another Covid-19 infection wave, with estimated daily cases rising from about 1,000 three weeks ago to 2,000 in the past two weeks.

It is driven mostly by two variants, the EG.5 and its sub-lineage HK.3, both of which are descendants of the XBB Omicron variant. Together, they account for more than 75 per cent of cases now.

“This is the second Covid-19 infection wave we have encountered this year. Like for the last wave, which occurred from March to April, there are no plans to impose any social restrictions,” said Mr Ong.

“We will treat this as an endemic disease and live with it. After all, there has been no evidence to suggest that the new variants are more likely to lead to severe illnesses compared to the previous variants, and all indications showed that current vaccines continue to work well in protecting us from severe illnesses if we’re infected by these new variants.”

While there are no plans to impose social restrictions, Mr Ong reiterated that the virus that causes Covid-19 has not become milder since the pandemic crisis. “It is us who have become stronger and more resilient”, and that is because of vaccinations, as well as safe recovery from infections, he said.

He was speaking on Friday at the opening of the Stepping Stones Rehabilitation Centre and addiction medicine ward Serenity Centre at the Institute of Mental Health.

Drawing from the findings of a recent Ministry of Health (MOH) study, Mr Ong said that for those who are best protected from Covid-19 – with a minimum of three mRNA shots and a natural infection which they recovered from, all within the last 12 months – the rate of severe illness is about 10 per 100,000 population.

For those who are least protected, with no vaccination or infection, the incidence rate of falling severely ill from the virus is over 50 per 100,000 population – five times more than those who are well protected.

The most important finding is that individuals who are well protected with three mRNA shots plus an infection, but who acquired these more than 12 months ago, have the same incidence rate of severe illness as those who are not vaccinated or protected by a previous infection.

“This is a clear indication that protection wanes, and it happens at around the 12-month interval,” he said.

The MOH study calculated the incidence rate of severe illness recorded during the peak of the last infection wave in April 2023 for the various groups of people.

The Health Minister advised seniors aged 60 and above, or those who are medically vulnerable, to keep their vaccination up to date to ensure mild Covid-19 symptoms and fast recovery.

“The infection will give you protection against severe illness if you encounter the virus in the future. Before this protection wanes, if you take another jab, the protection gets renewed again,” he said.

“We should expect more people to fall sick, and if so, hospitalisations will go up, waiting times will go up. If you are a senior, or medically vulnerable due to an underlying illness, please take the necessary precautions, such as wearing a mask in crowded areas.”

Meanwhile, the Health Sciences Authority has given full approval to Paxlovid, an oral antiviral drug for treating Covid-19, for use in Singapore from October.

The tablet is for the treatment of mild to moderate Covid-19 in adult patients who are at high risk of progressing to severe disease, to reduce the risk of hospitalisation and death.

Paxlovid was granted Pandemic Special Access Route Interim Authorisation in January 2022 for use in Singapore as an emergency therapeutic product.