First, Thailand will mix doses of Sinovac and AstraZeneca vaccines

By Panarat Thepgumpanat and Panu Wongcha-um

BANGKOK (Reuters) – Thailand will use AstraZeneca Plc’s COVID-19 vaccine as a second dose for those who received Sinovac’s vaccine as the first dose in a bid to increase protection, he said on Monday.

The move is the first publicly announced mix-and-match of a Chinese vaccine and a vaccine developed in the West, as a new preliminary Thai study has raised doubts about the long-term protection of the two-dose Sinovac vaccine.

“This is about improving protection against the Delta variant and building a high level of immunity against the disease,” Health Minister Anutin Charnvirakul told reporters, adding that the second dose of AstraZeneca would arrive three times. or four weeks after the first shot of Sinovac.

No specific study on mixing Sinovac and AstraZeneca has been published, but a growing number of countries are considering combining different vaccines or giving a third booster dose, as newer, more contagious variants may escape approved vaccines.

The announcement came a day after Thailand’s health ministry said 618 out of 677,348 medical workers who received two doses of the Sinovac vaccine were infected from April to July. A nurse died.

Neighboring Indonesia has also reported major infections among medical and frontline workers who are fully inoculated with the Sinovac vaccine.

Thailand now plans to give boosters of imported mRNA vaccine to its frontline workers – who received imported Sinovac before the locally made AstraZeneca vaccine was made available in June. Indonesia is considering similar boosters.

On Monday, a preliminary Thai study of 700 medical workers reported that the rate of protection of Sinovac as measured by the level of antibodies ranged between 60% and 70% during the first 60 days after the second dose, but the rate steadily increased. declined over time and seemed to halve. every 40 days.

“According to our research, if our medical staff received two doses of Sinovac (…) The researchers have not yet published the complete data of their study.

“They can do it between AstraZeneca or Pfizer when it happens, and we’ll continue to monitor their antibodies,” Sira said.

A representative from AstraZeneca declined to comment on Thailand’s decision, saying only that the vaccination policy is up to each country.

Sinovac did not respond to requests for comment on Monday.

Sinovac spokesman Liu Peicheng last month told Reuters that preliminary results from the blood samples of the vaccinated showed a three-fold reduction in the neutralizing effect against the Delta variant and suggested that a third shot of Sinovac could cause a longer lasting antibody reaction.

Thailand implemented its tightest coronavirus restrictions in more than a year in Bangkok and surrounding provinces on Monday, amid a growing wave of highly transmissible Alpha and Delta variants, with cases reaching nearly 10,000 a day and record deaths.

The measures, initially lasting two weeks, include widespread suspensions by airlines and bus companies, a curfew, shopping center closures and a five-person limit for gatherings.

The vast majority of the total of 345,027 cases and 2,791 deaths have been since April after nearly a year of largely controlling the virus, but its mass vaccination rollout started slowly, which only began. than last month.

(Written by Kay Johnson. Editing by Martin Petty)

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