_Figure 1: Vaccination rates by income group_ _Figure 2: Vaccine rollout rates by income group_ <!-- Start of picture text --> Share of people vaccinated against COVID-19, Mar 22, 2022 How many vaccine doses were administered in the previous 12 months?<br>Per 100 people in the population. The value shown for each date is the total number of vaccine doses administered<br>in the 12 months preceding that date. All doses, including boosters, are counted individually.<br>Share of people with a complete initial protocol Share of people only partly vaccinated<br>Upper middle income<br>Upper middle income 76% 4.8% 81% 100 High incomeWorldLower middle income<br>Low income<br>High income 74% 5.2% 79% 10<br>World 57% 6.9% 64%<br>1<br>Lower middle income 49% 10% 59%<br>.01<br>Low income 11% 14%<br>.001<br>0% 10% 20% 30% 40% 50% 60% 70% 80% Dec 15, 2020 Jun 4, 2021 Sep 12, 2021 Mar 22, 2022<br>Source: Official data collated by Our World in Data CC BY Source: Official data collated by Our World in Data CC BY<br>Note: Alternative definitions of a full vaccination, e.g. having been infected with SARS-CoV-2 and having 1 dose of a 2-dose protocol, are<br>ignored to maximize comparability between countries.<br><!-- End of picture text --> Data source: Ritchie et al. 2022 as of March 22, 2022.

Vaccine hesitancy refers to delay in acceptance or refusal of vaccination despite availability of vaccination services (MacDonald et al. 2015). It is not a new phenomenon, and some level of hesitancy exists for most vaccines, usually revolving around concerns about efficacy or safety. Even before the COVID-19 pandemic began, the World Health Organization (WHO) identified vaccine hesitancy as one of the top threats to global health (WHO 2019). The 2019 Wellcome Global Monitor from Gallup assessed general attitudes about the importance, safety, and effectiveness of vaccines across the globe prior to the onset of COVID19. Overall, on average, globally 7 percent of respondents either somewhat or strongly disagreed that vaccines are safe, and 5 percent either strongly or somewhat disagreed that vaccines are effective (Gallup 2019). Levels of vaccine hesitancy were lower in low- and middle-income countries compared with highincome countries. Across regions, countries in <mark>Eastern Europe and former Soviet states were among the least likely in the world to believe vaccines are safe and effective. A</mark> lthough these beliefs were expressed prior to the COVID-19 pandemic, they suggest that higher levels of COVID-19 hesitancy might be expected in Central and Eastern Europe as compared to other regions of the developing world. Furthermore, they suggest that concerns about safety are greater than concerns about efficacy.

Despite the importance of vaccinations against COVID-19, little is known about the prevalence of COVID19 vaccine hesitancy, and even less about the extent to which concerns about the COVID-19 vaccine are similar or different to longstanding concerns about other vaccines. Anecdotally, several factors likely contribute to COVID-19 vaccine hesitancy: for example, the accelerated speed of development of the COVID-19 vaccine, combined with its newness, has intensified concerns about unknown longer-term sideeffects. There are also reports of specific effects, such as of myocarditis in men under the age of 40 (Husby et al. 2022). Uncertainty about the duration of the vaccine’s effectiveness raises the possibility of needing annual vaccination. The availability of multiple types of vaccination, each with its own levels of efficacy and dosing schedule may also lead to confusion, and hence hesitancy. Relatedly, both the type of vaccine (e.g., mRNA) and country of origin of the vaccine have been identified as a factor in hesitancy. For example, a study from Brazil showed greater rejection among Brazilians for vaccines developed in China and the Russian Federation, as compared to vaccines from the United States or England, which could be related to local politics and foreign policy (Gramacho et al. 2021), as well concerns about data reporting related to vaccine development/approval (Bucci et al. 2021). Wong and colleagues (2021) reported greater hesitancy toward vaccines produced using the mRNA technology in Southeast Asia as compared with Europe and the Americas.

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