Singapore residents who took Sinovac vaccine can have 2 doses of Pfizer or Moderna

A doctor shows a box of Sinovac COVID-19 vaccines at a private clinic in Singapore on July 6, 2021. (Photo by Then Chih Wey/Xinhua via Getty Images)
A doctor shows a box of Sinovac COVID-19 vaccines at a private clinic in Singapore on 6 July, 2021. (PHOTO: Xinhua via Getty Images)

SINGAPORE — Those who have received the Sinovac COVID-19 vaccine locally as well as returning Singapore residents who have received a vaccine overseas different from the two under the national vaccination drive would be allowed to receive two doses of the Pfizer-BioNTech or Moderna vaccine.

This was revealed by the Ministry of Health (MOH) director of medical services Kenneth Mak in response to a reporter's question in a COVID-19 virtual doorstop interview on Wednesday (7 July).

"We have not stopped them although data is still lacking considering what the effectiveness is of this strategy using two different vaccines – we call this a heterologous vaccination strategy," said Associate Professor Mak.

He pointed out that there are some theoretical benefits that may suggest that these vaccinated individuals would get good results but stressed that there is "not much real-world data available" for verification.

"But nonetheless, if there are those who are eligible to receive the vaccination from the national vaccination programme, we will allow them to register but we will advise them about the fact that evidence is not available concerning how well the response (is) if they had received other vaccines before," Prof Mak added.

These individuals would then weigh the pros and cons before agreeing to proceed to be administered with the vaccines under the national vaccination drive, he added. Prof Mak did not mention how many of such requests have been made here, if any.

Yahoo News Singapore has reached out to the MOH for clarifications on whether Singaporeans who have opted to receive either the Pfizer-BioNTech or Moderna jabs here for their first shot are allowed to receive the other vaccine under the programme.

A growing number of countries are looking at switching to different COVID-19 vaccines for second doses or booster shots, as several medical studies to test the efficacy of switching vaccines are underway.

A recent Oxford study found that a mixed schedule, where a shot of Pfizer's vaccine is given after an AstraZeneca shot, produced more antibodies than two AstraZeneca shots.

As of Wednesday, over 3.7 million people in Singapore – some 65 per cent of the population – have received their first dose of the COVID-19 vaccine, while 2.1 million have been fully vaccinated.

Authorities are targeting to have two-thirds of the population fully vaccinated by National Day, which falls on 9 August.

Those who have received the Sinovac's CoronaVac vaccine locally are not included in Singapore's national vaccination numbers. As of 3 July, 17,296 people here have received one dose of the Chinese-made vaccine.

Clinical trials for the Sinovac vaccine have shown that its efficacy rates range from 51 per cent to about 84 per cent against symptomatic disease, while both Moderna and Pfizer-BioNTech/Comirnaty vaccines have shown results of over 90 per cent.

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