Current levels of public reluctance to be immunized with  a forthcoming COVID-19 vaccine are so high that the resistance would in fact pre-empt many countries from reaching sufficient levels of “community” immunity, according to a new study of vaccine hesitancy among people in 19 of the most COVID-impacted countries around the world.

The study of 13,436 people, published in Nature Medicine on Tuesday, also reveals that “vaccine hesitancy” is growing worldwide, although are also significant variations in vaccine acceptance between countries and regions. On average, only 71.5 percent of respondents would definitely take a safe and effective COVID-19 vaccine. This is well below the bar of near universal acceptance (typically 95% for other diseases) that is usually needed to build so-called ‘herd immunity’, and means that there are tens of millions of potential vaccine avoiders globally. 

“It will be tragic if we develop safe and effective vaccines and people refuse to take them. We need to develop a robust and sustained effort to address vaccine hesitancy and rebuild public confidence in the personal, family and community benefits of immunizations,” warned Scott C. Ratzan, a study co-author. 

“We found that the problem of vaccine hesitancy is strongly related with a lack of trust in government. Vaccine confidence was invariably higher in countries where trust was higher,” said Jeffrey V. Lazarus, a study coordinator. 

Vaccine hesitancy, defined by the WHO Strategic Advisory Group of Experts (SAGE) on Immunization as a “delay in acceptance or refusal of vaccination despite availability of vaccination services,” could inhibit global control of the pandemic. 

The study included respondents over the age of 18 across 19 of the top 35 countries most impacted by COVID-19 in terms of cases per million population. Some 71.5 percent of respondents reported that they would likely take a vaccine if it was proven safe and effective, whereas some 14 percent of people would hesitate and 14 percent would refuse altogether.

Countries with the highest vaccine acceptance rates, over 80 percent, were predominantly in Asia – China and South Korea  – with a strong association between trust in government and willingness to accept a COVID-19 vaccine. Mexico and the United States had rates of around 75-76 percent.  Meanwhile, middle-income countries, including Brazil, India, and South Africa, also had a moderate to higher tendency towards vaccine acceptance (75 for India and 85 percent for Brazil).

The countries with the lowest vaccine acceptance rates were European countries and Canada, with Russia, Poland, and France displaying the least acceptance – where only 54 to 58 percent of respondents reporting that they would take the COVID-19 vaccine. 

Variation within national populations were strikingly linked to age, gender, education level, and income. For instance:

• Older respondents over the age of 65 were more likely to accept a vaccine compared to younger people;  
• Men were less likely than women to agree to get vaccinated;
• People with higher education levels (bachelor’s or postgraduate degree) were more likely to accept the vaccine;
• Respondents earning over $32 a day were more likely than those earning less than $2 a day to take the COVID-19 vaccine. 

In countries with medium and high COVID-19 incidence and mortality, respondents had a higher likelihood of vaccine acceptance. 

Interestingly enough, respondents across all countries reported that they would be less likely to get the COVID-19 vaccine if it were mandated by employers, as it could be perceived as limiting freedom of choice and forcefully imposing the employers’ interests. 

Building Public Trust in COVID-19 Vaccines – Complex Endeavour Needing Consistent Messaging

“Trust is an intrinsic, and potentially modifiable, component of successful uptake of a COVID-19 vaccine,” states the study’s authors, from the Barcelona Institute for Global Health, the London School of Hygiene and Tropical Medicine and the City University of New York. Building trust and addressing vaccine hesitancy are complex endeavors, requiring clear and consistent communication from governments and public health institutions to improve vaccine literacy and public confidence, they also advise.  

The COVID-19 pandemic has been accompanied by an infodemic that has flourished in widespread fear and uncertainty. Misinformation has increased rapidly, particularly on potential COVID-19 vaccines. This, along with the politicization of the vaccine development and approval process in many countries, could contribute to intensifying vaccine hesitancy. 

Since June, when the survey was conducted, populations have become even more skeptical of COVID-19 vaccines, according to more recent polls. A survey conducted by the New York Times and Siena College in mid-October found that 33 percent of US respondents would definitely not or probably not take a vaccine, after approval by the US Food and Drug Administration (FDA). 

Similarly, a poll conducted by STAT and The Harris Poll found that the percentage of the US public willing to get vaccinated decreased from mid-August to early October, from 69 percent to 58 percent. 

“Vaccine misinformation can be as contagious and as dangerous as the disease it helps to spread,” said Dr. Tedros Adhanom Ghebreyesus, Director General of the WHO at the Global Vaccination Summit in September. 

In the context of the current dynamic and changing landscape, continued research on vaccine hesitancy globally is needed to help governments, policymakers, health professionals, and international organizations design vaccination programs and organize communication campaigns. 

“What is true about the potential public acceptance of a COVID-19 vaccine is equally true for a TB vaccine should we get one that is more effective – there will be considerable work to do by administrators to educate communities about its benefits,” said Grania Brigden, Director of the TB Department at the International Union Against Tuberculosis and Lung Disease (The Union) – where news about the study’s findings were launched during their 51st global conference.

Image Credits: Kerry Cullinan , Nature Medicine.