A fourth COVID-19 vaccine dose can significantly reduce the risk of severe symptoms from lung inflammation, which often require the patient to be put on a ventilator, and the associated risk of dying, said Dr. Opart Karnkawinpong, director-general of Disease Control Department, citing the latest assessment report on vaccinations administered between May and July, when the BA.4 and BA.5 sub-variants of Omicron variant were spreading rapidly in Thailand.
The assessment was conducted jointly by the public health emergency operations centre and the centre to assess the efficacy of COVID-19 vaccines of the Disease Control Department.
According to the findings, two vaccine doses can reduce the risk of lung inflammation requiring a ventilator by 60% and the risk of death by 72%. Three vaccine doses can reduce the risk of lung inflammation requiring a ventilator by 83% and the risk of death by 93% and the fourth dose can eliminate the risk of serious symptoms from lung inflation and death almost completely.
Dr. Opart said, however, that the effectiveness of vaccines in preventing the onset of serious symptoms in people over 60 is lower than it is in younger people for the same vaccine doses.
If a fourth dose is given, the effectiveness in both groups of people will be the same, he said, adding that the effectiveness of the third vaccine dose will last up to six months, while cautioning that a person can be infected even though they have received booster doses, but the risk of severe symptoms or death will be minimal.
As Thailand enters a post-pandemic era, with the virus being reclassified as communicable disease under watch, Dr. Opart said that the Disease Control Department has been accelerating vaccinations to reach the target set.
He said that people must adjust to the new normal lifestyle, by wearing face masks when in public or crowded areas, maintaining social distancing and regularly sanitizing their hands.
