With their loud and effective campaigns, anti-vaxxers could hurt efforts to build COVID-19 herd immunity

Herd immunity could prove impossible without public willingness to be vaccinated

  • COVID-19 will not be dealt with until herd immunity is developed, either via widespread infection or an effective vaccine coming into play that is manufactured on a scale sufficient to be distributed around the world. 
  • Immunity of around 70% of the population may be enough, but surveys show that vast swaths of the population in the U.S. and the U.K. may refuse to take a vaccine for COVID-19, mistrusting vaccines in general or a new vaccine in particular.
  • Adding to the challenge, anti-vaxxer communities have proven to be very effective at spreading their message and pushing their agenda, particularly on social media. Their success could prove dangerous for the rest of the world and stretch out the pandemic.

VANCOUVER. Back in 2017, the man that may have done more than any other to push anti-vaccine sentiments in the world had a direct hand in a measles outbreak in the United States.

Andrew Wakefield was a British doctor who led the writing of a paper “ discredited almost immediately” that linked vaccines and autism. Many people read the paper. A lot fewer read the follow up. Wakefield, now living in Texas, remains an avid anti-vaxxer.

In 2017, he travelled to Minnesota with other anti-vaxxers and spoke to various audiences, including a Somali American community that was receptive to his message. In that particular community, vaccination rates for children under 10 fell from 92% to 40%. The next year, 79 people contracted measles, a disease that had been all but eradicated previously. 

If that anti-vaccination attitude carries through to a COVID-19 vaccine, it may be impossible to reach the level of herd immunity necessary to do away with the pandemic. 

(See Vaccines: Level of mistrust remains high despite overabundance of data)

The challenge of herd immunity

How much is enough when it comes to herd immunity? Is it enough for half of the population to be vaccinated or immune? Is it two thirds? 

“Apparently, 70% is the magic number for herd immunity to take place,” said Sam Fazeli, Director of Research for EMEA for Bloomberg Intelligence in a podcast. “What happens if 25% of the population choose to make the vaccine a political thing and not take it, whether they are antivaxxers or not? Then, of course, they are at risk and the other 75% have some immunity.”

“The problem, of course, is that if you have a virus that roams around in 25% of a very large population, you continue to give it the opportunity to continue to infect, of course, and also to mutate, which is what we don’t want.” 

Speaking to CNN on June 28, Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, said he would be satisfied with a vaccine that is effective between 70% and 75% of the time, but that requires a significant portion of the population be vaccinated. 

Many people in the U.S. say they would not be willing to take a COVID-19 vaccine and that could make it difficult to reach the levels of herd immunity needed to contain the virus. The most effective vaccine to date has been the measles vaccines, which is as much as 98 % efficient. 

In a May poll in the U.S. done by CNN, a third of respondents in the U.S. (33%) said they would not take a COVID-19 vaccine. 

“There is a general anti-science, anti-authority, anti-vaccine feeling among some people in this country,” Fauci said. 

When a vaccine is developed, it may not be effective 100% of the time. Having a third to a quarter of the population refuse to take a vaccine that is only 75% effective may leave such a big gaping hole in the network of protection that it makes it impossible for a return to some kind of normalcy.

Chances are that none of the new vaccines for COVID-19 will be 100 % effective. More likely, they will be closer to 70 % effective. And that means that more people have to be vaccinated to reach the 70 % threshold of immunization necessary for herd immunity to take hold.

“Dr. Fauci’s comment that he would ‘settle’ for a coronavirus (vaccine) with 70-75 % effectiveness must be viewed in the context that this requires near 100% vaccination of the US population achieved through education and consistent, pro-active science-based messaging and leadership at the local, state and national levels,” Dr. Russell Medford, chairman of the Center for Global Health Innovation and the Global Health Crisis Coordination Center told Salon

“There is a general anti-science, anti-authority, anti-vaccine feeling among some people in this country.”

Dr. Anthony Fauci

Enter social media

A variable that is throwing a wrench in the calculations is a resurgence in the number of people who are hesitant about vaccines or completely against them, often as a matter of belief and seldom based on sound and demonstrable facts. 

Overall, the number of people who oppose vaccines is far smaller than the number who want them, but anti-vaxxers are loud. Anti-vaxxers have proven to be good lobbyists and campaigners, targeting people who are on the fence and putting them off vaccines with surgical precision. 

A recent study published in Nature of posts on Facebook in 2019 either pro or against vaccines found anti-vaxxers frequently engaged with people who are on the fence.  

“Although smaller in overall size, anti-vaccination clusters manage to become highly entangled with undecided clusters in the main online network, whereas pro-vaccination clusters are more peripheral,” noted the Nature study led by Neil F. Johnson that was published in May. Johnson leads the Complexity and Data Science initiative at George Washington University in Washington D.C.

For the study, Johnson and his team analyzed 1,300 Facebook pages with almost 100 million followers. The study shows how misinformation spreads. During an outbreak of measles in 2019, the number of followers of anti-vaxxer pages jumped 500%. 

Preliminary findings from other studies suggest this is happening not just on Facebook but other social media networks as well, noted Nature

A year before COVID-19 began spreading seriously in the U.S., Facebook reduced how much misleading medical advice it allows on its site and moved to vet information from organizations that “have publicly identified verifiable vaccine hoaxes”. 

World needs a vaccine

The newfound success anti-vaxxers are having in spreading fear and their message could not come at a worst possible time. The SARS-CoV-2 virus that causes COVID-19 continues to spread around the world, virtually unchecked. Social distancing measures have helped some countries slow down the spread of the pandemic but there are really only two ways for it to be actually stopped: herd immunity or vaccines. 

A whole host of potential vaccines are being tested in sites around the world. Trials are underway in Brazil and the United Arab Emirates, the U.S., Canada and China among others. A Chinese company is working to test a vaccine in Canada, another is pushing forward with trials in Brazil. In the U.S., Moderna Inc. is leading the race and reported on July 14 positive results from a Phase I study of a vaccine that will start Phase II trials on July 27. 

A single vaccine development program will not be enough to do away with the virus. History suggests that nine out of 10 of those new vaccines will fail but, even then, no single company can produce enough vaccines to cover the entire world. It is important that there be multiple successful vaccines in multiple locations in order for the world to have a chance of beating down the virus. 

An effort underway led by the Coalition for Epidemic Preparedness Innovation (CEPI) has laid the groundwork to manufacture several billion doses of still unapproved vaccines relying on a network of 200 developers and manufacturers around the world. CEPI is backing nine vaccines, three of which are being developed using mRNA or DNA technologies. There are currently no vaccines of these types in the world that are approved for distribution. 

This effort comes with its own built-in challenges of aligning dozens of disparate regulators and also preparing for the possibility of having to manufacturing vaccines developed with new technologies for which there are no manufacturing facilities in place. 

“Right now, we know we can do the two billion doses that we have as our kind of our minimum target,” James Robinson, a biopharma executive that is leading CEPI’s manufacturing effort, told Reuters. Some 14 governments are backing CEPI’s efforts to lay the groundwork for manufacturing a vaccine, along with the Bill and Melinda Gates Foundation and the UK’s Wellcome Trust. 

Not everyone wants a vaccine

Unfortunately, the world seems to be fighting against the virus with one hand tied behind its back. Not only is there skepticism about new COVID-19 vaccines that are being pushed through at record speeds but there are also rising concerns about vaccines in general. 

The increase in fear coupled with logistical challenges caused by widespread lockdowns have led to falling rates of vaccination among children in countries around the world. 

(See Anti-vaxxers: Vaccine hesitancy rears its head around the world as agencies work to reach everyone)

“An unintended consequence of social distancing has been parents avoiding the doctor’s office, even for routine medical care,” Dr. Robert Frenck, a professor of pediatrics at Cincinnati Children’s Hospital Medical Center told The Enquirer in Cincinnati, US. There, there has been a 50 % drop in the administration of measles vaccines. “If this were to continue, it will only be a matter of time before we have widespread outbreaks of measles, as well as other preventable infections.”

For example, from the middle of March to the middle of April, the U.S. Vaccines for Children programs ordered 2.5 million fewer influenza vaccine doses and 250,000 fewer measles vaccine doses. 

(See Vaccination: Stalled progress makes old diseases new again)

The American Academy of Pediatrics has urged parents to not let vaccination schedules slip amid the pandemic and pointed to this decline in vaccination rates. 

A third of Americans say they would refuse to take a COVID-19 vaccine when it becomes available. 

In the U.K., a recent poll found a similar portion of people would refuse a vaccine, even though by some estimates as many as 82% of the population would have to be vaccinated to stop COVID-19. The U.K. study was commissioned by the non-profit Center for Countering Digital Hate.

Pew Research Centre survey found that only 54% of black adults in the U.S. would be willing to take a COVID-19 vaccine if one was available today. Only 74% of white adults would be willing to take it. The figures are striking, in part, because black populations throughout the country have been disproportionally affected by the novel coronavirus. According to Pew, black Americans make up 13% of the population but 24% of all coronavirus deaths. 

The US Food and Drug Administration is pre-emptively taking steps to address anti-vaxxer concerns. Among other things, it has shifted the goal posts on the success on any vaccine to include counts of the number of people that take it. 

“While the FDA is committed to expediting this work, we will not cut corners in our decisions and are making clear through this guidance what data should be submitted to meet our regulatory standards,” said the FDA’s Commissioner Dr. Stephen Hahn in a statement on June 30. “This is particularly important, as we know that some people are skeptical of vaccine developmental efforts.”