Expert says 4th shot ‘not needed yet’

While a booster is useful, a fourth shot of Covid-19 vaccine against the dominant Omicron variant is not yet necessary for most people, according to Dr Prasit Watanapa, dean of the Faculty of Medicine at Siriraj Hospital.

He said those who have received three shots should not rush to get a fourth as there is not enough evidence showing people need to get another dose every three to six months.

A recent study by Imperial College London suggested the general public should get a booster shot three months after receiving their second jab, and that a booster of either AstraZeneca or Pfizer can enhance efficiency against Omicron by 55%-80%.

In contrast, it found that people who only receive two doses of any vaccine may have no immunity against Omicron — or just 20% at best.

“There…