The Ministry of Public Health is studying how long immunity induced by a fourth shot of Covid-19 vaccine lasts, key information required before it decides when a fifth shot will be needed.
"We are still collecting the data found in blood tests to see how much immunity produced by the third and fourth jabs remains. The information we have so far is insufficient for us to say when a fifth shot will be necessary," said Dr Opas Karnkawinpong, director-general of the Department of Disease Control (DDC).
Those who have not yet received a fourth shot should do so immediately, he said.
Having two shots of a Covid-19 vaccine was found in previous studies to be about five to six times more effective than receiving none at all in preventing death from the virus, while a booster was found to be 30 to 40 times more effective in preventing an infected patient from dying, he said.
There have been no records in Thailand to date of anyone dying from Covid-19 after receiving four jabs, Dr Opas said.
People aged 60 and over and those with underlying health conditions are especially urged to get their third and fourth boosters.
As of yesterday, 22.15 million doses of a third shot and 2.28 million doses of a fourth shot had been administered, according to the DDC.
Meanwhile, two urgent tasks must be handled ahead of the Songkran holiday, Deputy Prime Minister and Public Health Minister Anutin Charnvirakul told a meeting of high-level health executives from the ministry yesterday.
The first is to prepare all healthcare facilities for an expected jump in the number of new patients, said Dr Sura Wisetsak, deputy permanent secretary for public health.
The second is to protect the elderly, and other at-risk groups, from severe symptoms by getting as many as possible a booster shot, she said.