Fourth jab necessary as immunity drops even after 3rd dose: Dr Yong
A third and even a fourth Covid-19 vaccine jab is necessary to prevent serious infection, expert virologist Dr Yong Poovorawan wrote on his Facebook page on Thursday.
He stressed that vaccines cannot prevent infection, but they can reduce the severity of the disease, especially for vulnerable people.
Yong pointed out the necessity to possess high immunity all the time because Covid-19 has a fast incubation period.
“A study on two Covid-19 jabs provided a good result, but immunity subsequently dropped as time passed,” he said, adding that the immunity provided by the third jab dropped as well.
He explained that it was necessary to stimulate both B cells to prevent infections and T cells to reduce severity of the virus and boost recovery, especially among vulnerable people.
Yong said it would be simple to administer the fourth jab in order to boost immunity to a high level.
“The virus’s vaccine resistance is another factor for boosting immunity to a higher level than usual," he said, adding: “So far, we have found that the severity of the disease declined when many people were vaccinated.”
