He said we could not get rid of SARS in 2003 and it became a global pandemic. After that, we tried to create herd immunity to stop it from spreading.
To achieve herd immunity, at least 60 to 70 per cent of the population must be vaccinated.
Yong said the Delta variant spread quickly, causing a new wave.
We knew a vaccine could reduce disease severity, deaths, and patients in hospital. However, it cannot completely eradicate a pandemic so herd immunity in this case cannot entirely prevent the disease from spreading, he wrote.
With influenza, the vaccine also could not prevent infections but it could prevent deaths.
Yong said the Covid-19 vaccine looked promising at first because it was 90 per cent effective in reducing symptoms, which was much higher than influenza with only 50 per cent.
However, the vaccine efficiency is high only for the first two to three months, then immunity decreases and the virus will mutate into different strains.
This decreases the efficiency of the vaccine within six months so doctors encourage getting booster doses to increase immunity.
He mentioned that France is developing the highly efficient inactivated Valvena vaccine by combining two adjuvants, Alum and CpG.
According to results of the study, there are hopes in Europe that this vaccine will be the most effective.
Yong added that everyone, especially people in risk groups, must be vaccinated to prevent death.
We cannot hope to achieve totally effective herd immunity so Thailand must vaccinate most of its people as quickly as possible, he said.
The Public Health Ministry aims to administer 100 million doses of vaccine by December 5.
Published : November 24, 2021
By : THE NATION