Could anti-vaxxers hinder vaccination efforts?

In the early stages of vaccine development, the number of people who didn’t trust vaccines was higher than it is now in some parts of the world.

For example, British Health Secretary Matt Hancock said the anti-vaxxer movement is not growingin the UK. On the contrary, there is an increasing number of people who want to get vaccinated against Covid-19.

Although there are no exact numbers of how many anti-vaxxers exist in every country, the number of people who trust vaccines has been increasing in some countries like the US and Turkey. 

That having been said, there is a potential threat that anti-vaxxers may prolong the pandemic if a high number of people refuse to take the vaccine.

So, how does one achieve herd immunity - when a large portion of the public becomes immune to a disease, making its spread from person to person unlikely.

How many people need to be vaccinated for ‘herd immunity’?

Vaccination programs are already underway in several parts of the world, but how much of the population should be vaccinated?

There are several studies attempting to determine ‘herd immunity’ for the Covid-19 pandemic.

Thanks to several mathematical models, herd immunity threshold (HIT) for coronavirus is predicted to be between 60 percent to 80 percent.

Although some predictions for HIT in the early days of the pandemic were quite low, some of them around 6 to 21 percent, the estimates since have shifted the numbers upward.

Despite not specifying a specific number for coronavirus HIT, the World Health Organisation (WHO) suggests the vast majority of the world population should be vaccinated. If not, nearly 90 percent of people around the world remain susceptible to this virus.

There are several uncertainties about the coronavirus like the number of asymptomatic cases, how long immunity lasts for, and how it might differ on a case by case basis. These challenges have kept the WHO from giving a concrete estimate for herd immunity threshold.

Top US infectious diseases expert Anthony Fauci, who is an adviser both to Donald Trump and the incoming Joe Biden administration, has increased its estimates for herd immunity.

Dr Fauci estimates that around 60 to 70 percent was required at the onset of the pandemic. Last month, he increased the HIT to 70-75 percent in television interviews.

However, last week, Fauci told CNBC News that HIT could be around75 to 85 percent.

"We really don't know what the real number is. I think the real range is somewhere between 70 to 90 percent. But, I'm not going to say 90 percent," he told The New York Times.

“When polls said only about half of all Americans would take a vaccine, I was saying herd immunity would take 70 to 75 percent,” Dr. Fauci added.

“Then, when newer surveys said 60 percent or more would take it, I thought, ‘I can nudge this up a bit,’ so I went to 80, 85.”

The needed HIT predictions for coronavirus by Fauci is close to the measles HIT which requires a 90 percent threshold.