Singapore: Infectious diseases expert David Lye calls out misinformation about Covid-19 vaccines, including Gabriel Oon Chong Jin’s promotion of Sinovac


The Straits Times

Infectious diseases expert David Lye calls out misinformation about Covid-19 vaccines

Salma KhalikSenior Health Correspondent

  • Published Jun 7, 2021, 4:36 pm SGT


SINGAPORE – A senior infectious diseases specialist, Associate Professor David Lye, has spoken up against misinformation being spread about Covid-19 vaccines by doctors, among others.

In a Facebook post on Monday (June 7) titled “Why fake science and anti-vaccine groups are dangerous in a pandemic”, the clinician-researcher at the National Centre for Infectious Diseases (NCID) said he needs to correct certain messages and petitions making the rounds which have caused him to have sleepless nights.

Some of these were from a group of doctors including a Dr Paul I.W. Yang, and a Dr Oon Chong Jin, a private cancer specialist, he said.

Comments from Dr Oon, who had been involved in testing the hepatitis B vaccine here more than 30 years ago, on Mount Elizabeth Medical Centre’s website and in various chat groups.

Dr Oon claimed that the Pfizer vaccine “is useless now and obsolete in the presence of mutations”.

He had promoted the use of Sinovac for everyone, including children, saying it could protect against the B1617 variants which had ravaged India. He claimed that the Pfizer and Moderna mRNA vaccines could not do this.

Prof Lye said all those claims are wrong.

On vaccinating the young, he noted that while they do not usually have severe Covid-19 infections unless they have health problems, they carry as much virus as adults if infected, and can infect adults with poor immunity and older adults, who may become sick.

A study in Britain showed that Pfizer and another vaccine by AstraZeneca reduced household transmission by 50 per cent to 60 per cent. “These doctors claimed that mRNA vaccines do not reduce transmission,” he noted.

The mRNA vaccines are among the most effective vaccines for Covid-19, he said. They reduce symptomatic Covid-19 by 95 per cent, reduce hospitalisation for the severe form of the disease by more than 90 per cent, and prevent transmission by more than 60 per cent.

There is a wealth of data from the United States, Britain and Israel on their safety, he said. “Importantly, mRNA vaccines are effective against United Kingdom’s B117 (93 per cent), South African B1351 (75 per cent to 90 per cent) and (India’s) B16172 (88 per cent) variants.

“There is hardly any data on Sinovac against the variants. Laboratory studies showed that Sinovac may not work well in Brazilian B1128 and South African B1351 variants.”

He said: “Although these doctors claimed Sinovac is superior to mRNA vaccines against variants, there is little data to confirm it is effective for B16172, and there is data to suggest it is less effective against other variants.”

As to claims that mRNA vaccines were developed in a rush, Prof Lye said all Covid-19 vaccines were developed rapidly, and “in fact, Sinovac and Sinopharm were approved in China before the trials were completed”.

“Singapore and China have strong relationships. There is no reason for Singapore not to approve Sinovac. But approval requires data judged to be adequate,” he said.

The Health Sciences Authority (HSA) is still awaiting a reply from Sinovac on its queries, he pointed out. “With the latest update on criteria for mRNA vaccines, there are very few reasons why a person cannot take mRNA vaccines. These doctors are pressuring HSA to ignore rigorous review process.”

He also debunked the oft-cited belief that Sinovac is safe because it uses traditional methods.

“Even though inactivated whole virus vaccine is an old technology, it is not harmless and we still need to watch out for side effects. In the 1960s, two inactivated vaccines for measles and respiratory syncytial virus led to more severe disease, and were withdrawn.”

He added that hepatitis B vaccine, which Dr Oon had championed, is not a killed whole virus vaccine like Sinovac either.

He noted how these doctors quoted a study that showed how RNA from the Covid-19-causing virus could be integrated into human cells and said: “While this has been quickly debunked by scientists as an artefact of the laboratory methods, these doctors failed to understand that mRNA from vaccines do not last for more than two days in our body and are different from viral RNA from Covid-19 infection.”


Received via WhatsApp: The claims or Dr Gabriel Oon Chong Jin.

Finally a doctor in Singapore talks about the failure if the vaccine most Singaporeans have been administered to.

The message originated from Dr Gabriel Oon Chong Jin, a retired oncologist who is a pioneer in liver cancer research here.

Dr Oon, 82, played a key role in Singapore’s hepatitis B vaccination programme that began in the late 1970s. Hepatitis B is a liver infection caused by a virus.

When contacted by TODAY on Friday, Dr Oon, who last practised at Mount Elizabeth Medical Centre, confirmed that the content of the message was from him.

In the message, he wrote that mutations in the spike protein of the coronavirus causing Covid-19 has altered its antigenicity — or its ability to bind to cell walls.

The spike protein is the part of the virus that it uses to penetrate human cells so that it can bind with the cells more effectively and cause infection.

When the antigenicity changes, vaccines that use the new mRNA technology such as Pfizer-BioNTech cannot recognise the mutant variant such as the B1617 one.

Only a vaccine such as Sinovac that has an inactivated virus “with all its seven antigens” can still produce an immune response even when one antigen of the active invading virus is affected by mutation, Dr Oon wrote.

He added that the B1617 variant had successfully infected vaccinated frontliners and airport staff members, as well as school children in Singapore.

“Pfizer is useless now and obsolete in the presence of mutations on (the) spike gene,” the message read.

He also said in the message that “China vaccines” can overcome the B1617 variant and that he had written in to the authorities to consider using Sinovac.

The Sinovac vaccine may be suitable for children, and even babies, but at a lowered dosage, he added.

When asked by TODAY to comment more about his concerns, Dr Oon stressed again that mRNA vaccines are “useless” against the B1617 mutant and that the variant should be seen as a “new infection”.

“I would say it is a time of emergency, a time to change and use another vaccine such as Sinovac, which we already have in stock,” he said, referring to the shipment of the vaccine Singapore received in February and pending approval for use here.

Dr Oon continued: “If we keep vaccinating people with mRNA vaccines like Pfizer, we are endangering the lives of so many people around us who will still get infected, not to mention the person who is vaccinated.”

It is a doctor’s duty to call immediately for a change of treatment if it is not working for a patient who has a life-threatening condition, he said by way of example.

In offering his views on Covid-19, he said: “I did it for the love of my country and humanity.”

Dr Oon’s circulated message on WhatsApp mentioned that he had reached out to various Cabinet ministers, including Health Minister Ong Ye Kung, on the mRNA vaccines and Sinovac.

Dr Oon confirmed that he had done this, at around the time news broke of the B1617 variant.

He declined to give more details on the recommendations he proposed to the Government as mentioned in the message.

TODAY understands that MOH is aware of Dr Oon’s circulated message since last month and had addressed some of his concerns in the same statement last month issued regarding the open letter by the doctors to parents.

That statement did not address Dr Oon’s concerns on how effective mRNA vaccines are on mutated variants.



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