Khairy explains why herd immunity no longer realistic

 

Last year, Malaysia had set the goal of vaccinating 70 percent of its population against Covid-19 in order to achieve herd immunity against the disease, and thus facilitate a return to pre-pandemic normalcy.

With the appearance of the Delta variant, however, Health Minister Khairy Jamaluddin said achieving herd immunity is no longer considered realistic due to two factors – the variant’s high transmissibility, and vaccines’ reduced effectiveness against it.

He told a press conference yesterday that the vaccine coverage needed to reach herd immunity is calculated based on the disease’s basic reproduction number (R0).

The higher the R0, the greater the vaccine coverage needed. Once the threshold is reached, then the disease can be brought under control or even eradicated even if some people are still unvaccinated.

R0 is a measure of a disease’s transmissibility. For example, an R0 of three would mean each infected person could infect an average of three other people throughout the course of his disease, and the cycle then begins anew with three newly infected people.

For the original Covid-19 strain in Wuhan, Khairy said the R0 was between two and three.

“But what changed the stance of many countries is the appearance of the Delta variant. The R0 has increased to between six and 10, and some say it could be even higher.

“The Delta variant has also changed vaccine effectiveness and the virus’ ability to spread. Its infectivity is far higher than the original virus […]

“Based on information from the World Health Organization (WHO), no country has attained this so-called ‘herd immunity’.

“Moreover, the WHO said the main goal of vaccination is the reduce cases and death, whereas achieving herd immunity is no longer a priority nor something realistic,” he said.

New normal

Khairy was explaining his speech in Parliament on Thursday where he told MPs that the appearance of the variant has “thrown out the herd immunity calculations” and made it unfeasible.

He said this is why the government has changed tack and no longer seek to achieve herd immunity, but to vaccinate all eligible persons against Covid-19.

This means ensuring all adults and adolescents would complete their vaccinations by the end of the year, and vaccinate children too once this is approved by the National Pharmaceutical Regulatory Agency (NPRA).

In addition, third doses and booster shots will be provided to certain vulnerable groups, once the clinical guidelines for doing so have been prepared.

“This strategy is very important for us for containing the spread of Covid-19, reducing the ICU admission rate, and reducing the death rate so that we can enter the endemic phase safely,” he said.

On Sept 1, Khairy had indicated that Malaysia will move away from the current total containment approach to Covid-19 and treat it has an endemic disease.

This would mean accepting a “new normal” such as wearing face masks, as more sectors are allowed to reopen and the rules are simplified. The shift is expected to take place by October. - FMT