Most health workers have been inoculated with the Chinese Sinovac vaccine, but concerns exist over its efficacy against the Delta variant that is driving Thailand’s current outbreak.
Health workers should be first in line for booster shots with AstraZeneca or the 1.5 million Pfizer jabs just donated by the US, said Centre for Covid-19 Situation Administration (CCSA) adviser Udom Kachintorn.
Reporting results from a National Vaccine Committee meeting on Tuesday, Udom explained that other countries and the World Health Organisation had yet to establish guidelines on mixing and matching vaccines.
However, Thailand must take urgent action to tackle the fast-spreading Delta variant, which now accounts for 50 per cent of cases in Bangkok and 30 per cent elsewhere, he said.
If officials let the situation continue like this, the health system would collapse, he added.
He also noted that both Pfizer and AstraZeneca are due to produce new vaccines to combat virus variants by year-end or early next year.
Udom confirmed that existing vaccines are less effective against variants. He cited a UK study that showed Pfizer offers 7.5 times less protection against Beta and 2.5 times less against Delta, while AstraZeneca offers 9 times less protection against Beta and 4.3 times less against Delta.
As for Sinovac, a study by NSTDA in collaboration with Chulalongkorn Research Centre found that it offers 4.9 times less protection against Delta. Pfizer’s mRNA vaccine offered the best immunity against variants, followed by AstraZeneca and Sinovac.
A study to determine the best brand for booster shots is being conducted by Siriraj Hospital and Chulalongkorn University, with results expected within a month.
The 20 million doses of Pfizer also procured by Thailand will be used to protect the at-risk group of people aged 60-plus and those with chronic conditions, added Udom.
Published : July 06, 2021
By : The Nation