SINGAPORE, June 8 — The expert committee on Covid-19 vaccination under the Singapore Ministry of Health (MOH) has refuted online claims asserting that messenger ribonucleic acid (mRNA) Covid-19 vaccines are ineffective against viral variants. It also said it is crucial that medical professionals “do not spread unsubstantiated and unscientific information”.

In a statement yesterday, the committee said that based on its continued review of data and evidence, the current mRNA Covid-19 vaccines used here — Pfizer-BioNTech and Moderna — continue to be “safe and highly effective”, and “show protection against variants of concern”.

The committee noted that some social media messages have also claimed that inactivated virus vaccines such as Sinovac would provide superior protection.


“The inactivated virus Covid-19 vaccines have variable protection and there is currently no evidence to suggest that inactivated virus vaccines demonstrate higher vaccine efficacy against variants of concern than the mRNA vaccines.” 

This clarification by the expert committee comes after several doctors aired their views against mRNA Covid-19 vaccines in the past weeks.

Last week, a petition was started online by a group of doctors urging the Government to include Sinovac in the national vaccination programme.


Some doctors among this group also wrote an open letter earlier to parents asking them to think through carefully before choosing to inoculate their children against Covid-19.

A separate circulated WhatsApp message by Dr Gabriel Oon, who led Singapore’s hepatitis B vaccination project in the 1970s and 1980s, said that mRNA vaccines are ineffective against the B1617 variant that was first detected in India.

Heading the expert committee on Covid-19 vaccination is Dr Benjamin Ong, senior advisor to the director of medical services at MOH and senior vice-president of health education and resources at the National University of Singapore.

Among the members of the committee is Dr David Lye, who is the director of infectious disease research at the National Centre for Infectious Diseases (NCID).

Dr Lye had shot down some of the doctors’ claims in a Facebook post yesterday, adding that Covid-19 vaccines using mRNA technology are the most effective against the coronavirus, including its variants.

He noted that, on the other hand, there is hardly any data on how the Sinovac vaccine performs against the variants.

The committee added: “It is critical that medical professionals do not spread unsubstantiated and unscientific information.

“The public has a right to expect medical professionals to give advice based on fact and not on unproven assertions... The public should rely on reputable sources of scientific and medical information, and verify opinions shared by others against these.”

It added that the authorised Pfizer-BioNTech and Moderna Covid-19 vaccines are safe and effective, and it is recommended that medically eligible persons in Singapore should be vaccinated with them.

The expert committee said that Pfizer-BioNTech and Moderna mRNA vaccines have in various studies “consistently shown to be highly efficacious, at around 90 per cent, especially in protecting against severe Covid-19 disease and hospitalisation”.

These were demonstrated in various trials and actual roll-outs in the United States, United Kingdom and Israel.

Emerging data continues to show that the mRNA vaccines are also effective against the B1617 variant.

For instance, a study in the UK showed that two doses of the Pfizer-BioNTech mRNA vaccine confer about 88 per cent protection against symptomatic Covid-19 even with the delta or B16172 variant.

“While further studies are required before a definitive conclusion can be made, the available data globally indicates that substantial protection is preserved,” the committee said.

It acknowledged that protection conferred by any vaccine is not 100 per cent, and that with the emergence of new variants, vaccine-breakthroughs — where people still fall ill despite being fully vaccinated — can occur.

However, it added that “the detection of asymptomatic to mild infections locally with the delta variant does not indicate a lack of protection”.

Rather, the findings showed that the infected people have mild or no symptoms, and this is in line with the global evidence that the mRNA vaccines have a high level of protection against symptomatic and severe disease.

The Pfizer-BioNTech and Moderna vaccines have been approved by multiple reputable international regulatory bodies, and their manufacturers have publicly released their detailed study protocols and openly published their findings to be scrutinised by the scientific community after peer review.

There is “reliable scientific evidence that (Pfizer-BioNTech and Moderna vaccines) are safe and effective, and the expert committee continues to strongly recommend that medically eligible persons should be vaccinated with them”, it added.

Vaccines produced to fight the coronavirus need a spike protein to trigger the human body’s immune system to develop antibodies. The spike protein on the surface of the virus helps it to enter human cells and cause an infection. 

A vaccine using the traditional inactivated virus approach has the whole spike protein, whereas mRNA vaccines do not have that but instruct cells to produce it to get an immune system response, Dr Lye said in reply to comments on his Facebook post.

Committee’s take on inactivated virus vaccines

The committee noted that the Sinovac vaccine has yet to meet the requirements for the Health Sciences Authority’s Pandemic Special Access Route, which helps to facilitate early access to critical novel vaccines, medicines and medical devices during a pandemic.

This is because more safety and quality data required for Sinovac to meet the standards of evaluation under this route are still pending.

Both Pfizer-BioNTech and Moderna are authorised under this route.

The Sinovac vaccine has shown “variable protection across multiple studies carried out internationally”, the committee said, with the most complete analysis of the vaccine showing a vaccine efficacy of 51 per cent on per-protocol analysis.

“The protection of Sinovac against newer variants such as the delta variant and under real-world conditions remains unknown,” the committee added.

It noted that Sinovac has been qualified by the World Health Organisation (WHO) under its Emergency Use Listing procedure for use only in persons aged 18 years and above.

Dr Oon had said in his circulated message that the Sinovac vaccine may be suitable for children, and even babies, but at a lowered dosage.

The committee said, however, that Sinovac has not been recommended by WHO for persons under 18 years old and so, it will not be an option in the meantime for children and adolescents globally or in Singapore.

MOH said last Friday that the 200,000 doses of Sinovac vaccines that Singapore has in stock will be released for free to licensed private healthcare providers to administer to adults under a “special access route”. — TODAY