SINGAPORE , Aug 1— The wave of Covid-19 infections driven by the Omicron BA.5 variant has been subsiding, with the week-on-week infection ratio dipping below 0.9 over the last week and set to fall further this week, said Health Minister Ong Ye Kung in Parliament today.

In terms of reported cases, about 30 per cent of Singapore’s population, or about 1.7 million people, have been infected with the Covid-19 virus, said Ong in response to a question from Member of Parliament (MP) Seah Kian Peng of Marine Parade Group Representation Constituency (GRC).

However, estimates based on blood samples monitored from routine polyclinic cases and other healthy volunteers for signs of previous infection indicate that 60 per cent of local residents are likely to have been infected with Covid-19, he added.

Despite the high infection rate, Ong said that this does not mean Singapore has “herd immunity” and that even if the infection rate hits 100 per cent, the country will not have achieved this status.

“By and large, scientists around the world do not think herd immunity is achievable because the virus will continue to mutate, escape the protection of vaccines and then infect people,” he said.

Instead, he said what is “achievable” is population protection against severe illnesses through vaccinations.

“This is what enables the healthcare system to weather through an infection wave even with high case numbers because the translation of case numbers into severe illnesses is very low,” he said.

Vaccinations among the elderly

Despite the push for vaccinations among the elderly, Ong said that 40,000 seniors aged 60 and above still have not received their booster shots, even though they are eligible, while another 40,000 seniors have not completed two doses yet.

“All of them are vulnerable to severe illnesses if infected, and we will continue to try to reach out to them through our mobile vaccination teams and through our home vaccination teams” said Ong.

He added that empirical data shows that after 10 months, the protective effect of three doses of mRNA vaccines remains very strong in preventing severe illnesses.

“That is why as of now, our recommendation is for those who are 80 and above to receive their second booster or fourth shot to better protect against severe disease.”

Re-infection rates

On the incidence of re-infections, Ong said that the Ministry of Health (MOH) has been “watching the re-infection numbers very closely, because it will inform us of the likely timing of future waves”.

Based on MOH’s observations, the chance of getting another infection for those who were infected over the last three months “is very rare”.

For those infected four to seven months ago, the probability of re-infection is about 3 per cent that of an uninfected person, while those infected with the Delta variant last year have a 20 per cent probability of getting infected again, compared to that of an uninfected person.

“Of course, this picture will change as time goes by, and the protective effect of prior infections will wane. Hence, having been infected by Covid-19 before should not be a reason to let your guard down,” said Ong.

He added that re-infections are taking place, albeit not as frequently here compared to other countries, but are likely to increase as the protection from prior infections wanes.

MOH will start including re-infection numbers in its daily reported case counts, he said.

Previously, MOH has reported the number of patients who have been infected every day. This means that the ministry only counts a patient once even if the patient has been infected twice.

“With more re-infections, from today, we will report the infection episodes instead of infected persons. This will be a more accurate reflection of the pandemic situation,” said Ong. — TODAY