SINGAPORE — A study of 1,000 household contacts of Covid-19 cases in Singapore has shown that messenger ribonucleic acid (mRNA) vaccines have an effectiveness of 69 per cent against the Delta variant of the coronavirus, regardless of symptoms, Health Minister Ong Ye Kung said. 

Speaking at a virtual press conference on Wednesday (July 7), he said the study by the National Centre for Infectious Diseases and the Ministry of Health (MOH) looked at household contacts of Covid-19 cases between September last year and the end of May this year. 

The findings are quite consistent with international observations, he added. 

Both the Pfizer-BioNTech and Moderna vaccines approved for Singapore's vaccination programme use mRNA technology.

“Recently, there was a reported figure from Israel that the Pfizer vaccine’s efficacy against infection is 64 per cent. Ours registered as 69 per cent, so it's roughly that,” Mr Ong said.

“And this data will be submitted for international publication as Singapore's contribution to the understanding of the Delta variant and the vaccines.”

The data also shows that the mRNA vaccines provide 80 to 90 per cent protection against symptomatic disease, and 93 per cent protection against severe symptoms requiring oxygen supplementation or intensive care and death.

“So among the local cases reported since April 11, only 1 per cent of those vaccinated require oxygen and none were admitted to the ICU (intensive care unit),” Mr Ong said.

In comparison, 10 per cent of unvaccinated individuals who were infected developed severe illnesses, he added. 

He thus urged members of the public who have received their first dose of the vaccine to rebook their second dose appointments earlier, so that the interval between their first and second doses is four weeks instead of six to eight weeks.

“We are not constrained by supply anymore and we have capacity to deliver more dosages. So remember, the earlier you can get your two doses, the better the protection against severe illnesses.”

MOH has been sending out SMS on phones to people with later appointments to ask them to move their second dose appointments forward, Mr Ong said, adding that 131,000 individuals have heeded the call so far and another 200,000 or so individuals have yet to do so.

At the current rate of vaccination, he said that the ministry expects 50 per cent of the population to have received two doses of the vaccination around the week of July 26.