Health Promotion Bureau Head warns against thinking of herd immunity now

By Rathindra Kuruwita

It was too early to talk about herd immunity, Head of the Health Promotion Bureau (HPB), Dr. Ranjith Batuwanthudawa said yesterday, addressing the media.

When asked whether there would be herd immunity after 70% of Sri Lankans were vaccinated, Dr. Batuwanthudawa said that there were a number of factors that needed to be considered as regards herd immunity.

“Measles is an example for herd immunity. We vaccinate babies at nine months and 99% of babies are vaccinated. The rule is that if 85% of kids are vaccinated for measles, herd immunity can be achieved. We started vaccinating for measles in 1983 and we have been vaccinating people for close to 40 years. So, we have universal coverage and the measles virus has not changed,” he said.

On the other hand, the coronavirus had mutated into several variants, Dr. Batuwanthudawa said. Those who had been vaccinated could get infected and transmit the virus, he said.

“As you can see it’s a whole new ball game. Last year, two major variants, the alpha and the delta caused havoc in almost all countries. We also don’t know what new surprises the virus has to offer. So, we shouldn’t look at the high vaccination percentage and think we are nearing herd immunity. It is a recipe for disaster.”

Unless all countries in the world got the pandemic under control, new variants would emerge and given the globalised nature of the world such variants would spread across the world in weeks, Dr. Batuwanthudawa said. Sri Lanka had fully vaccinated about 12 million people and apart from Kegalle district, 80% of those above 30 in other 24 districts had been vaccinated, he said.