SINGAPORE, Dec 16 — People in Singapore who received two doses of the Sinovac vaccine have been observed to have lower protection against severe disease when infected by the Delta coronavirus strain, compared to those who were fully vaccinated with the messenger ribonucleic acid (mRNA) vaccines from Pfizer-BioNTech and Moderna.
This was based on a recent study conducted here by the National Centre for Infectious Diseases (NCID) and the Covid-19 data management and analytics team of the Ministry of Health (MoH).
“This supports the need for three doses of the Sinovac-Coronavac vaccine as a primary series,” NCID and MoH said.
In a news release yesterday (December 15), they said that the study specific to Singapore’s population was done from October 1 to November 21 and covered 1.25 million people.
The people who were part of the research were aged 40 and above and who received two doses of the vaccines under the national vaccination programme.
“The analysis accounted for differences in age, gender, race, housing type and the daily differences in infection rate,” they said.
This is lower than that for the Pfizer-BioNTech vaccine, which was 90 per cent, and for the Moderna vaccine, which was 97 per cent.
“These results support the need for three doses of Sinovac-CoronaVac vaccines as a primary series to attain better protection against severe disease, defined as requiring oxygen and intensive care, and death due to Covid-19,” NCID and MoH said.
People who have received two doses of the Sinovac vaccine are recommended to receive a dose of an mRNA vaccine as their third dose as part of their primary vaccination series.
Otherwise, they should complete the primary series of vaccination with a third dose of the Sinovac vaccine.
NCID and MoH said that their recommendation is substantiated by international findings.
Based on preliminary data from Chile, people who received the Pfizer-BioNTech vaccine as their third dose after two doses of Sinovac “had a 95 per cent reduction in the risks of infection”.
“In contrast, the risk reduction in persons who received Sinovac-CoronaVac as the third dose was 71 per cent.
“The antibody rise was also observed to be around 27 times higher when the Pfizer-BioNTech vaccine was received as the third dose compared to if Sinovac-CoronaVac vaccine was received,” NCID and MoH said.
In Singapore, anyone eligible to be vaccinated will be able to receive their booster doses of the mRNA vaccine five months after completing their primary vaccination series, or two doses.
“We will continue to monitor the vaccine effectiveness of the mRNA and non-mRNA vaccines, including how they are enhanced by a third dose or a booster dose. In the meantime, all persons who are eligible for their boosters should get boosted when it is offered to them,” they added.
Earlier this month, MoH reminded those who have had their first two doses of the Sinovac or Sinopharm vaccines to take their third.
The ministry warned that they will lose their fully vaccinated status in the new year if they do not do so by December 31. ― TODAY
