respondents who are either unwilling to get vaccinated or uncertain about their decision. Analogously, we categorize as willing those who have either already been vaccinated or are willing to do so.

|**Question**<br>**Table**|**Respondent group**<br>**1: Summary of survey questions**|**Answer options**|**Availability**|
|---|---|---|---|
|**(1) Vaccine uptake**||||
|Have you been vaccinated for COVID-19?|all who know of start of vaccination campaigns|Yes, No, Not sure|all countries|
|Where did you get vaccinated?|all vaccinated|One location per jab received|all countries|
|What are your main reasons for getting vaccinated for COVID-19<br>[apart from protecting your health]?|all vaccinated|Up to two reasons (3 in Kenya)|all countries|
|**(2) Vaccine acceptance among the unvaccinated**||||
|Are you planning to be vaccinated for COVID-19?|all who know of start of vaccination campaigns|Yes, No, Not sure|all countries|
|When a vaccine to protect you from COVID-19 is available to you,<br>are you planning to be vaccinated?|all who do not know of start of vaccination<br>campaigns|Yes, No, Not sure|BFA, MWI, NGA, TZN|
|If an approved vaccine to prevent coronavirus was available right now<br>at no cost, would you agree to be vaccinated?|all who do not know of start of vaccination<br>campaigns|Yes, No, Not sure|KEN|
|What are the main reasons why you want to get vaccinated for<br>COVID-19 [apart from protecting your health]?|all willing but unvaccinated|Up to two reasons (3 in Kenya)|all countries|
|Why are you not sure or not planning to get vaccinated?|all hesitant|List of reasons for hesitancy|all countries|
|**(3) Barriers of access**||||
|Do you know if your country has started COVID-19 vaccination?|all|Yes, No|BFA, MWI, NGA, TZN|
|Do you know if a vaccine for COVID-19 is available in Kenya?|all|Yes, No|KEN|
|Why have you not received the COVID-19 vaccine yet?|all willing but unvaccinated who know of start of<br>vaccination campaigns|Up to two reasons|MWI, NGA, TZN|
|What do you think are the main difficulties that you will/would<br>encounter to get the vaccine?|all willing but unvaccinated|List of barriers|KEN|
|**(4) Information sources and channels**||||
|Who/what (institution/body/entity) are your sources of information<br>regarding COVID-19 vaccines?|all who know of start of vaccination campaigns|List of information sources|BFA, MWI, NGA|
|Which source of information do you trust the most for reliable<br>information on COVID-19 vaccines?|all who know of start of vaccination campaigns|Select one among mentioned info<br>sources|BFA, MWI, NGA|
|Through what channels do you receive the information from the<br>source you trust the most?|all who know of start of vaccination campaigns|Select one info channel|BFA, MWI, NGA|
|**(5) Ambassadors of vaccination**||||
|Would you be more likely to receive the COVID-19 vaccine if any of<br>the following individuals/authorities receive or recommend the<br>vaccine?|all hesitant|Select yes or no for list of<br>individuals/authorities|all countries|
|Whose recommendation to get vaccinated for COVID-19 would you<br>trust the most?|all hesitant that had named at least one<br>individual/authority that could encourage them|Select one among previously<br>selected potential ambassadors|BFA, MWI, NGA, TZN|
|How likely are you to encourage others to get the COVID-19 vaccine?|all willing to get vaccinated or already vaccinated|Five point Likert scale|BFA, MWI, NGA, TZN|
|**(6) Social factors in vaccine attitude formation and uptake**||||
|Out of 10 people in your community, how many do you think have<br>been vaccinated or are willing to be vaccinated for COVID-19?|all|Number from 0-10|BFA, MWI, NGA, TZN|
|Who in your household mainly decides whether the adult household<br>members will get vaccinated for COVID-19?|all who know of start of vaccination campaigns|Each for themselves; All adults<br>together; Household head; Name<br>other household member|BFA, MWI, NGA, TZN|

Our analysis draws on the questions summarized in Table 1. These questions group into six broad themes. First, we ask about vaccine uptake among respondents and ask those who have already been vaccinated about the vaccination process. The second theme relates to vaccine acceptance among those who have not been vaccinated yet. These questions gauge the extent of vaccine hesitancy among respondents and the main reasons for their vaccine attitudes. The third theme covers the barriers that keep respondents from getting vaccinated with a particular focus on those who have not been vaccinated yet despite being willing to. Fourth, we ask respondents about their main sources and channels of information on COVID-19 vaccines to identify possible communication strategies for national vaccination campaigns. Theme five is devoted to potential ambassadors that could promote vaccination among respondents. Finally, the sixth theme turns to the social context in which vaccine attitudes are formed and looks at the transmission of vaccine attitudes and uptake decisions within communities and households.

In the analysis we present population-weighted means at the country-level for each variable, computed using the recalibrated phone survey weights. The full results are presented in the supplementary files.

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