Thai study makes strong case for use of mRNA vaccine as booster dose
Eminent virologist Professor Yong Poovorawan on Friday affirmed that a booster dose of mRNA vaccine is 22 times better for protecting against the Omicron strain than an inactivated Covid-19 vaccine.
Yong, who heads the Centre of Excellence in Clinical Virology at Chulalongkorn University’s Faculty of Medicine, posted on his Facebook wall that the findings of the clinical research will be sent in a preprinted form to the MedRxiv for publication later on Friday. He will also send the result to other international medical journals for publication.
He said the research had been carried out in cooperation with Dr Thaneeya Duangchinda, a researcher of the Medical Biotechnology Unit of Siriraj Hospital.
The study was carried out among four groups of 60 people each who received two doses of inactivated vaccine for six months. All people in the four groups received two Sinovac vaccines for six months.
The first group received an inactivated Sinopharm vaccine for a booster dose, the second group the viral vector AstraZeneca vaccine, the third group the mRNA Pfizer vaccine and the fourth group the mRNA Moderna vaccine.
Yong said the studied groups were later tested with serum dilution in the so-called FRINT [focus reduction neutralisation test] to check their immunity against the Delta and Omicron variants.
The study found that those given the Sinopharm vaccine had 22 times lower immunity against the Delta and Omicron strains of both imitated and real virus samples than those given the mRNA vaccine. Those who were given the viral vector vaccine as a booster dose also enjoyed higher immunity than those given an inactivated vaccine, Yong added.
“In conclusion, using AZ and mRNA vaccines [Pfizer or Moderna] as a booster dose provides better protection against the Delta and Omicron strains and this is a method being practised in Thailand,” Yong said.
