Severa; vials of COVID-19 vaccine set on a table.

Mitigating Hesitancy Key to COVID-19 Vaccine Readiness

| 4 Minute Read
Health | Global Health Security
Countries around the world are rapidly assessing and advancing their readiness for COVID-19 vaccines, but success ultimately hinges on whether individuals are willing to accept the vaccine.

Vaccines are one of the most cost-effective public health interventions, saving millions of lives each year. They are our best chance of eradicating COVID-19, which has had one of this century’s most devastating impacts on humankind, with high death tolls and major disruptions to economies and everyday life. Vaccines historically take years to develop, requiring rigorous safety and efficacy testing. Because the race to develop COVID-19 vaccines globally is progressing rapidly, countries need accelerated efforts for equitable access and timely distribution, especially to those in low- and middle-income countries (LMICs). LMICs, in particular, may lack appropriate financing, an enabling regulatory and policy environment, strong supply chain systems, a trained health workforce that is adequately distributed, and other systems necessary to vaccinate large populations quickly. Countries are already making substantial efforts to assess and advance their readiness for COVID-19 vaccines. Success anywhere, however, hinges on whether individuals are willing to accept the vaccine.

Understanding “Vaccine Hesitancy”

According to the World Health Organization’s (WHO) Strategic Advisory Group of Experts on Immunization, vaccine hesitancy is a “delay in acceptance or refusal of vaccination despite availability of vaccination services.” In 2019, the WHO identified vaccine hesitancy as one of the leading threats to global health.

Individuals’ refusal of vaccines has limited the control of vaccine-preventable diseases, fostered disease outbreaks, and wasted public health resources. Vaccine hesitancy manifests differently across people, places, and vaccine types, and the reasons for it vary accordingly, from fears of nefarious covert effects to concerns about inadequate testing. For example, in 2003 in Northern Nigeria, outright refusal obstructed polio eradication efforts when extremist Islamists turned their communities against immunization. Religious and political leaders in densely populated states had started rumors that the vaccine was tainted with cancerous agents and HIV. The environment of disinformation, mistrust, and violence culminated in the killings of nine vaccinators in 2013, and entire communities refused polio immunizations. In 2015, after the government of Nigeria and its partners launched aggressive, coordinated vaccination campaigns and immunization services, vaccine hesitancy was reduced significantly and the WHO removed Nigeria from its polio-endemic list.

Erroneous scientific research also can spur doubt among populations, even when a vaccine’s efficacy has already been proven. The measles, mumps, and rubella (MMR) vaccine, introduced to the United States in 1971, led to a sharp decline in mumps cases and the elimination of measles and rubella in the early 2000s. Despite these successes, the vaccine became controversial in 1998, after Andrew Wakefield published a hypothesis that the MMR vaccine can result in autism in children. Wakefield’s work was retracted in 2010 when it was found to be flawed, and later was determined to be fraudulent. Despite the retraction, Wakefield’s assertions have persisted as part of a strong anti-vaccination movement in the United States and Europe, with a quarter of U.S. parents continuing to express hesitancy to the MMR vaccine by delaying or spacing vaccinations, or refusing to have their children vaccinated at all.

Conscious campaigns against vaccines have fueled distrust and limited uptake. In some countries, people have blamed vaccines for sterility or accused international bodies of using vaccines as a tool for covert population control. In Kenya, this issue exploded in 2014: Catholic priests and the Kenyan Catholic Doctors Association accused the WHO of lacing tetanus toxoid (TT) vaccines, used to prevent neonatal sepsis, with pregnancy-related hormones that caused sterility among women of childbearing age. Priests encouraged congregants to boycott the TT campaign; these claims were also taken up by politicians. The doctors’ association claimed to have tested vaccine samples and found human chorionic gonadotropin hormones – which stimulates the body to produce progesterone to maintain a pregnancy – but the laboratory that was used did not have the capabilities for such an analysis. Although the accusations were proven false, the outcry threatened to derail the TT vaccination campaign.

Individuals’ refusal of vaccines has limited the control of vaccine-preventable diseases, fostered disease outbreaks, and wasted public health resources.

Timely vaccination of a large proportion of the population must occur to achieve herd immunity and to break the chain of transmission. Estimates for COVID-19 range from 70 to 90 percent. A recent study that reviewed data from more than 130 countries found that anti-vaccination groups are using social media to heavily influence COVID-19 vaccine hesitancy with the deliberate spread of disinformation and conspiracy theories. Anti-vaccination enthusiasts have recently increased their presence on social media to forge new connections and to build support for their conspiratorial views, which could have disastrous impacts on the successful rollout of COVID-19 vaccines.

Building Vaccine Confidence for COVID-19

How can we combat vaccine hesitancy and boost confidence in the COVID-19 vaccines? Multicomponent interventions that target populations based on unique needs work best. For example, public health agencies can conduct targeted communications campaigns based on an understanding of the factors that might influence and build the trust of a specific sub-population. Health care workers can increase awareness and address specific concerns during regular clinical encounters. Similarly, religious and community leaders have the power to dispel myths and allay fears among followers. In Nigeria, it was the involvement of religious and traditional leaders that aided the successful uptake of the polio vaccine. Social mobilization, which relies on community-based participatory approaches, improved uptake of HPV and polio vaccination in low- and middle-income settings, while telephone calls or letter reminders have been effective at increasing vaccine uptake in higher-resource settings. In Israel, during a recent silent polio outbreak, uptake of the oral polio vaccine was strongly associated with media exposure. Social marketing strategies and principles have improved vaccine acceptance in Australia and the United States for childhood immunization, and in several resource-limited settings for Hemophilus influenzae type b (Hib) vaccine. Lastly, non-financial incentives, such as food, are known to positively impact the uptake of vaccines among resource-poor populations.

As we move forward with COVID-19 vaccination, it will be critical to continuously monitor vaccine hesitancy across populations and quickly devise new or expanded mitigation strategies to combat it. Studies that monitor hesitancy, such as those conducted by the Vaccine Confidence Project, will be key to understanding the issues, as well as government and community monitoring to ensure the success of vaccination efforts. Time is of the essence, however, and the global community must act now to preemptively promote vaccine confidence and increase acceptability across the board. Investing in multifaceted efforts that reduce hesitancy and promote confidence is critical for COVID-19 vaccines and could enhance the effectiveness of interventions for other existing and new life-saving vaccines, too.

*Banner image caption: Dimitris Barletis /

Posts on the blog represent the views of the authors and do not necessarily represent the views of Chemonics. 

About Dr. Baz Semo

Dr. Baz Semo is a medical doctor and public health specialist with 30 years of experience in infectious diseases and health systems strengthening. She served as the managing director of global health programs at Chemonics. Prior to Chemonics, Baz worked for ministries of health in several African countries, U.S. academic institutions, U.S. nonprofits, and the…

About Julie Becker

Julie Becker is the former senior vice president of Chemonics’ Global Health Division, where she led the division’s strategy and growth and its work in health systems strengthening, HIV, malaria, and private sector engagement, among other areas. Julie worked on the ground in sub-Saharan Africa, Asia, Latin America, the Caribbean, and the US. Before Chemonics,…

About Mariam Reda

​​Dr. Mariam Reda is a former Director in Chemonics’ Global Health Division.