In a Facebook post on Tuesday, expert virologist Dr Yong Poovorawan said Covid-19 is a new disease and its vaccines are also new. Hence, the best way of tackling the virus is to gradually accumulate knowledge on what works to reduce the risk to vaccine recipients.
"So far, we know that two vaccine shots can prevent severe symptoms and death from Covid-19. However, to maintain high immunity, a booster or third jab is required," he said.
"Based on this, everybody should get at least two jabs and then a booster when they can.
"There is no need to think about getting a fourth shot just yet. Instead, we should wait until we know more about Covid-19 or until a new generation of vaccines is developed," he suggested. He said waiting is the best thing to do since each jab needs to be administered at a suitable interval to allow the vaccine enough time to stimulate immunity.
"Furthermore, getting too many jabs can increase the risk of side effects," he added.
"There is evidence that recipients of three mRNA vaccines develop myocarditis after the second shot and lymphadenopathy after the third shot, though they had shown no side effects after the first jab.
"If you have already registered for the fourth jab with a private vaccine importer, it is advisable to postpone it for now and wait at least six months after your third jab," the expert said. "We don't know what will happen in the future. There could be a new variant of the virus or a new type of vaccine may become available."