KUALA LUMPUR, Feb 19 — A medical doctor has cleared the air over uncertainty regarding the various Covid-19 vaccines available, stating that many of the fears surrounding the new mRNA technology in vaccines are unfounded.

Consultant pediatrician Dr Musa Mohd Nordin, with the KPJ Damansara Specialist Hospital, said he aimed to ensure the public can make better informed choices based on good science, and not be frightened by fear-mongering and fake news spread by anti-vaxxers. 

He was answering several questions on his Twitter handle, one of which wanted to know if the Pfizer-BioNTech vaccine was safer for older individuals or those with health issues.

The inquirer added that a friend with doctors in her extended family said their relatives above 60 years of age have decided to take the Sinovac vaccine from China despite its lower efficacy as it was safer to use since by injecting inactivated viruses into the body, the body did not have to work as hard to produce antibodies.

The inquirer said that Pfizer-BioNTech’s vaccine has a 95 per cent efficacy rate but which required the body to work harder to produce antibodies, hence why it was more suitable for younger people and those without health issues.

Dr Musa initially agreed that the mRNA-based vaccines manufactured by Pfizer-BioNTech and American pharmaceutical corporation Moderna Inc are more efficacious at 95 per cent, while Sinovac’s vaccine efficacy varied at around 50 to 91 per cent.

"Both Pfizer and Moderna have published their Phase Three clinical trial results in the New England Journal of Medicine (NEJM) a top tier medical journal, while Sinovac and all the vaccines from China have never published their Phase Three trial results.

"However, Pfizer and Moderna’s Phase Three clinical trial have 73,000 subjects, while Sinovac in their press release only indicated 16,000 subjects in their Phase Three trials,” he said.

Dr Musa said Pfizer and Moderna have since rolled out about 140 million doses in about 60 countries, and that the publications of their trial results and its numbers are vital because they enable the validation of the companies’ claims about the efficacy and safety of their vaccines.

"For example, Israel has immunised about 75 per cent of their population with the mRNA-based vaccines, with the effectiveness of the vaccine in the real world experience was 94 per cent. This is very similar to the 95 per cent results in their Phase Three trials.

"Similarly, the United Kingdom’s Medicines and Healthcare products Regulatory Agency noted that Adverse Effects Following Immunisation (AEFI) were all minor in nature, which was also reported by the Lancet, another top-tier medical journal,” he said.

Dr Musa added that only one AEFI was reported, which was in the NEJM concerning anaphylaxis or a severe allergic reaction to venom, food, or medication, something which he said is very rare.

"I hope I have shown how meticulous the researchers and regulators have been before releasing the mRNA vaccines to the general public under Emergency Use Authorization (EUA) to ensure they are efficacious and safe.

"I however cannot say the same for the Sinovac vaccine or any of the other vaccines from China. I am just being objective and scientific and applying evidence-based medicine and best practices in vaccinology,” he said.

Dr Musa said that Sinovac was given early and limited use, similar to the EUA, by the Chinese government while still in the Phase Two trial period, a practice which he said is unthinkable in any first-world country.

"I am not sure what you mean when you say the Pfizer vaccine has to work harder to produce antibodies. Research has shown that Pfizer vaccines only produce the right type of antibodies since the mRNA only selects the neutralising antibodies which are protective.

"The classical technology used in Sinovac produces both neutralising and NON-neutralising antibodies. The latter antibody may not be protective, but may trigger Antibody Dependent Enhancement-like effects which have caused problems for the dengue vaccine, as an example. Thus far this has not been reported,” he said.

Dr Musa added the Pfizer-BioNTech vaccine is also very effective in those above 60 years old, many who have underlying health problems, and is not just suited for the younger ones and those without health issues as the inquirer implied.

"This has been proven in Israel, where most of those above 60 years old have been immunised and this has been associated with a more than 60 per cent reduction in severe Covid-19 cases and hospitalisations,” he said.