Boosters Needed to Extend Full Vaccination Status in Singapore

Vials of Pfizer and BioNTech's COVID-19 vaccine are seen in France, on Nov. 27, 2021. (Jeff Pachoud/AFP via Getty Images)

Singapore will review the validity period for full vaccination status as new variants emerge, said Health Minister Ong Ye Kung in a press release on Dec. 14, 2021.

Details on the validity period will be announced at the end of this year or early next year. Currently, a person is considered fully vaccinated after two doses of mRNA vaccines, or three doses of Sinovac or Sinopharm vaccines.

Individuals who have not yet been given a chance to get their booster shots or are ineligible for boosters will not see their full vaccination status lapse when the new policy kicks in.

Last Friday, the ministry announced extending booster shots to people as young as 18 years old. All eligible individuals will be able to obtain their booster shots five months after receiving two doses of mRNA vaccines.

Under the expanded program, about 54 percent of the total population in Singapore are expected to have received their boosters by the end of next January.

Individuals who choose to get Moderna boosters can walk into the designated vaccination centers without bookings, as there are more Moderna supplies available this month.

The two mRNA vaccines, Moderna and Pfizer/Comirnaty, “can be used interchangeably as boosters,” said Ong.

To ramp up the delivery of boosters, the monitoring time after a booster shot is shortened from 30 minutes to 15 minutes, as data in Singapore showed a “very low incidence rate of significant acute adverse reactions after taking boosters,” according to the health minister.

The slew of new measures came ahead of an “impending Omicron wave” and Ong’s reliance on a study from the United Kingdom that showed positive results for the effectiveness of the boosters. Although Ong did not specifically identify the study, the UK Health Security Agency recently preprinted a study on the effectiveness of COVID-19 vaccines against the Omicron variant.

“For two doses of Pfizer-BioNTech, vaccine effectiveness against Omicron infection dropped from about 90 percent one month after the second dose, to about 50 percent after three months and then 35 percent four months and beyond.

“This erosion of protection is quite fast. But then, two weeks after a booster, vaccine effectiveness against Omicron infection shot back up to 75 percent, which is encouraging. This means boosters work,” said Ong quoting the UK study.

The authors of the preprint also noted that “vaccine effectiveness against symptomatic disease with the Omicron variant is significantly lower than with the Delta variant.” The study has not been peer reviewed yet.

In Singapore, the number of daily confirmed cases, which peaked at more than 5,000 in October, now is often less than 500.

However, the health minister cautioned that “this peaceful state may not last long, for there is a potentially big Omicron wave coming our way, and we need to get prepared.”

Speaking on why Singapore is not shutting its borders to prevent Omicron from spreading into the country, Ong explained that it’s “not coherent” to switch to a zero-COVID policy and it’s “not realistic to stop Omicron from coming into our small city state.”

“To reduce the number of people who fall very sick, we still need to fall back on vaccinations and boosters. That remains our primary response to deal with the Omicron variant,” the health minister said.