The study was anonymous, and the informed consent of the participants was sought before they filled in the questionnaire. No compensation or incentives were given to the participants. The study was approved by the Health Research Ethics Committee of the Federal Medical Centre at Owo in Ondo State, Nigeria (FMC/OW/380/VOL.CX/74).

The study was performed in Ondo State, southwest Nigeria. Professional groups for HCWs in this questionnaire-based study included medical doctors, nurses, pharmacists, laboratory scientists, community health extension officers or workers, health assistants, and others. All respondents worked in Ondo State, southwest Nigeria. The questionnaire was open for about two months, from March 9, 2021, to May 11, 2021. A total of 564 participants answered the questionnaire. We excluded those who opened or started the questionnaire but answered less than one-tenth of the questions. The final study sample consisted of 557 participants.

First, we informed the leaders and some members of each HCW professional group about the study. A text message (via SMS) drafted by the authors was then posted by the leader or members of the group on the groups’ WhatsApp platforms on mobile phones. The SMS carried a link to the online questionnaire, where interested HCWs could voluntarily participate in the study. The online questionnaire was designed and conducted using Nettskjema [31]. The WhatsApp mobile app is the most popular means of disseminating information to HCWs in Ondo State, where all HCW professional groups have group WhatsApp platforms.

The participants were asked to give some basic demographic information and information about their work: their gender (man or woman), age group (<20, 20-29, 30-39, 40-49, 50-59, and >59 years), marital status (single, married, divorced, or widowed), level of education (secondary, university, postgraduate, or other), type of HCW (medical doctor, nurse, pharmacist, laboratory scientist, community health extension officer, health assistant, or other), and the type of health care facility where they worked (primary, secondary, or tertiary health facility; private hospital; or other). They were also asked to give information about any chronic illness (“yes,” “no,” or “I don’t know”) and prior COVID-19 infection (“yes,” “no,” “I believe I had the infection even though I did not do a test to confirm it,” or “I don’t know”).

The participants were asked about their trust in government information on COVID-19 and vaccines with the following question: “On a scale of 10 where 1= least trusted and 10=most trusted, how much do you trust the government regarding COVID-19 information and vaccine?”

The HCWs were requested to respond to 2 questions relating to highly circulated conspiracy theories: “I think COVID-19 vaccine is a means to implant digital microchips to track and control people” and “I think COVID-19 vaccine will alter my DNA or genetic information.” Responses to each of the statements included “strongly agree,” “agree,” “neutral,” “disagree,” or “strongly disagree.” The participants were also asked the following question: “If COVID-19 vaccine is available and free, will you take it?” The participants chose a response option from the following: “yes,” “no,” “I don’t know,” and “I will intentionally delay for months.” If participants were not willing to take the vaccine, they were asked why (possible reasons included “safety concern,” “lack of trust in the government,” “scared of COVID-19 vaccine,” “vaccine is against my religion,” and other reasons). They were further asked to choose their main trusted source or sources of information on COVID-19 and vaccines from the following: social media (ie, WhatsApp and Facebook), traditional media (ie, TV and newspaper), health authorities (state and federal), colleagues and friends, academic journals, and others.

We categorized responses to the question “How much do you trust the government regarding COVID-19 information and vaccine?” as 1 to 4 (low level of trust), 5 to 6 (medium level of trust), and 7 to 10 (high level of trust). We dichotomized the response to the statement “COVID-19 vaccine is a means to implant digital microchips to track and control people” by coalescing “strongly agree,” “agree,” and “neutral” into “yes” and “strongly disagree” and “disagree” into “no.” Likewise, we dichotomized “COVID-19 vaccine will alter my DNA or genetic information” by coalescing “strongly agree,” “agree,” and “neutral” into “yes” and “strongly disagree” and “disagree” into “no.” Lastly, we dichotomized the response to the question “If COVID-19 vaccine is available and free, will you take it?” into “yes” as “vaccine acceptance” and coalescing “no,” “I don’t know,” and “I will intentionally delay for months” into “vaccine hesitancy.” We used the resulting variable for the third logistic regression.

We used descriptive statistics to calculate and summarize all the variables as absolute values and percentages. We used multivariable logistic models to fit the following three dichotomized outcomes: (1) “COVID-19 vaccine is a means to implant digital microchips into people,” (2) “COVID-19 vaccine will alter my DNA or genetic information,” and (3) “If COVID-19 vaccine is available and free, will you take it.” These were used as the dependent variables in each of the 3 main logistic regressions. We used purposeful selection of independent variables for each of the 3 main logistic regression models [32]. Any independent variable selected for any of the 3 main models using this method was also used in all the models, that is, the same independent variables were used in all models.

All statistical analyses were conducted using Stata (version 17.0; Stata Corp). All P values were considered statistically significant at a level of <.05.

One main finding in this study is the relatively high proportion of health workers who believed that the vaccines contained microchips and that the vaccines could alter the recipients’ DNA or genetic information. More than a quarter of the respondents believed in 1 of these 2 conspiracy theories. We lack information about why so many of the HCWs believed in these misconceptions about the COVID-19 vaccines. Even though technologies that are different from older, long-established ones were used to develop the different COVID-19 vaccines, such as the mRNA vaccine technology utilized by Pfizer/BioNTech and Moderna [16] and the viral vector vaccine technology utilized by Janssen/Johnson & Johnson, AstraZeneca, and the University of Oxford [19], there are still no compelling justifications for HCWs to believe the misleading vaccine conspiracy theories. However, there are historical reasons, including alleged unethical practices by pharmaceutical companies in Nigeria, that may play a role in fueling skepticism toward vaccines in the country [33].

The central importance of trust has been underlined in studies focusing on vaccine hesitancy [34]. A lack of trust in the government and its institutions has also been highlighted as an important reason underlying vaccine hesitancy in Nigeria [35]. In our study, a higher level of trust in government information on COVID-19 vaccines was positively related to a lower risk of belief in conspiracy theories and an increase in COVID-19 vaccine acceptance and could therefore be an underlying explanatory factor. Simply put, not trusting the government may increase the likelihood of believing in conspiracy theories and decrease the acceptance of vaccines among HCWs.

Nigeria plays a central role in democracy in Africa and is the most populous country on the continent. However, the country has recently witnessed political unrest, violence, and terrorism. Mistrust in government could be related to a lack of government accountability in public-sector management [36], and there is a need to further strengthen security and governance to improve the population’s trust in its governing institutions [37].

More women believed in the microchip conspiracy and more men in the DNA conspiracy, but the differences in beliefs between the genders were only statistically significant for the latter (Table 4), suggesting that the respondents’ beliefs in conspiracies may occasionally be gender specific. There were also some contrasts between the different HCW groups, with the nurses and the pharmacists having the most respondents with conspiracy theory beliefs; as many as 45.8% (55/120) and 50% (5/10), respectively, believed that the vaccines could alter their DNA. The nurses and the laboratory scientists were the occupational groups with the highest proportion of believers (40/120, 33.3%, and 6/16, 37.5%, respectively) in the microchip conspiracy. When calculating adjusted ORs for belief in the conspiracy theories (Table 4), the nurses, the community health extension officers, and the “other” category stood out as having significantly higher levels of conspiracy theory beliefs. There were no clear patterns regarding the importance of age or marital status for belief in the 2 conspiracy theories.

Approximately three-quarters of the respondents were willing to take the COVID-19 vaccine, a higher proportion than previously reported among HCWs in northern Nigeria [38]. The level of trust in government was clearly related to an increased willingness to take the vaccine (Table 4). A prior study [39] found an increased willingness to take the vaccine in older respondents, and a similar but nonsignificant trend was found in this study [39]. In contrast to prior findings, the well-established risk factor for a more severe infection of having a chronic illness was not related to an increased willingness to take the vaccine [39]. However, no subcategorization was made in our study regarding type of chronic illness, and only some chronic illnesses are related to a worsened COVID-19 outcome. A lower willingness has been noted in particular among nurses in prior studies [26,38], and in our study, only half of the nurses stated that they were willing to take the vaccine, while this was the case with about three-quarters or more in the other professional groups. However, when calculating adjusted ORs (Table 4), the willingness to take the vaccine was not significantly different between the different professional groups. We lack data regarding why nurses seem to be the professional group with the highest belief in conspiracies, but it may be related to the contrasting groups, including the medical doctors, having more knowledge regarding vaccine technologies.

Probably unsurprisingly, a large proportion of these HCWs (253/557, 45.4%) obtained their trusted information about COVID-19 from social media—where we know much health-related misinformation is propagated [26,27]. In our study, those who stated they relied on government institutions as their main source of COVID-19–related information were significantly less likely to believe in the conspiracy theories (Table 4). Prior studies have also found that many HCWs rely on social media for COVID-19–related information [40]. A recent study found that there is an increasing belief in Nigeria that vaccines are unsafe [41]. This is likely in part fueled by social media misinformation [23,26,27].

We believe our study underlines the need to actively counteract misleading and false information on social media and to make sure that HCWs are given scientifically sound information on this important topic. This information should be given by different stakeholders (eg, the government and nongovernmental organizations) through different channels, including social media, in order to reach as many HCWs as possible. HCWs are clearly not immune to social media misinformation.

This study has some limitations that one should be aware of while interpreting the results. The study used the WhatsApp platforms of the various professional groups to distribute the questionnaire. Any member who was not on the platform or was not connected to the internet during the period of data collection would potentially not have been reached by our questionnaire. However, most members are usually on the professional groups’ WhatsApp platforms because this is where they obtain up-to-date group information and communicate among themselves across health facilities, cities, and towns. We lack detailed information regarding the number of people that were members of the different professional groups and received the invitation to participate; we are therefore not able to calculate an accurate response rate. However, studies with online recruitment typically achieve relatively low response rates, and this is likely to have been the case and a limitation in this study [42]. With our method of data collection, it was possible for a member of a group to answer the questionnaire multiple times. However, we do not see any reason why an individual would do so. The study was carried out in Ondo State, one of Nigeria’s 36 states. Keeping the limitations mentioned above in mind, we believe the study’s findings may be representative of HCWs in this state, as well as of neighboring southwestern states, which in many ways are relatively similar. It is more uncertain to what extent the study’s findings can be generalized to all of Nigeria, which is the most populous country in Africa and quite diverse in terms of ethnic groups, languages, and cultures.

A relatively high proportion of the HCWs expressed belief in the microchip or DNA conspiracy theories, or both, and only about three-quarters were willing to take the COVID-19 vaccine. A lack of trust in the government’s information and its institutions might explain both the belief in the conspiracies as well as the vaccine hesitancy. Health workers are not immune to misinformation, and social media plays an important part in fueling vaccine hesitancy. There is a need for stakeholders to actively counteract social media misinformation and to provide health workers with scientifically sound information.