The World Health Organisation and Unicef have reported the largest sustained drop in routine childhood immunisations in three decades, with 6m fewer children in Africa getting shots for diseases including tetanus, polio, diphtheria and measles over the past two years, and rising outbreaks threaten to reverse decades of progress against preventable diseases.
This, according to a study of 17 000 people across eight countries, is because public confidence in vaccines had declined dramatically across sub-Saharan Africa since the Covid-19 pandemic, reports MedicalXPress.
The study, published in the journal Human Vaccines & Immunotherapeutics, was carried out by a team from the London School of Hygiene & Tropical Medicine (LSHTM) and the Africa Centres for Disease Control and Prevention, and suggests there could be reasons for this reduction other than the disruption of vaccination programmes during the pandemic.
“Our study paints a worrying picture of declining vaccine confidence trends across many sub-national regions in sub-Saharan Africa, notably in the Democratic Republic of Congo, where confidence losses are particularly large,” said lead author Dr Alex de Figueiredo, a Research Fellow at LSHTM.
The team’s results could be an early warning sign of wider scale loss in vaccine confidence, say the authors. Critically, regional losses in confidence like this could lead to clusters of non-vaccinated people which could have a negative impact on “herd immunity” – the point at which a population is protected from a disease, either by enough people being vaccinated or by people having developed antibodies through having the disease.
The research involved face-to-face interviews with more than 17 000 adults (an even split of men and women) across eight sub-Saharan African countries: the Democratic Republic of Congo (DRC), Ivory Coast, Kenya, Niger, Nigeria, Senegal, South Africa and Uganda.
The experts used sampling methods to ensure an accurate cross-section of the population was represented and to gain a picture of vaccine confidence at both national and regional levels.
Interviewees’ age, sex, religion, employment status and highest education level were recorded to help the researchers to analyse whether social background affected confidence in vaccines. The interviews were carried out in 2020 and again in 2022, after the pandemic.
Respondents were asked to say how strongly they agreed with statements such as “Vaccines are important for all ages”, “Vaccines are important for children” and “Vaccines are safe”. They were also asked specifically about Covid-19 vaccines, rating their agreement that these would be important, safe and effective – both before they had been developed (in 2020) and then after they had been developed and rolled out, in 2022.
Findings showed a fall in people’s views that vaccines are important for children across all eight countries between 2020 and 2022, particularly in DRC (20% decline), followed by Uganda (14%) and Nigeria (10.5%).
In Nigeria and DRC, public confidence in vaccine safety and effectiveness also declined, and fewer people agreed that “vaccines are important for all ages” in Ivory Coast, Kenya, Nigeria, South Africa and Uganda.
When it came to Covid-19 vaccines, people thought they were less important in 2022 than they had in 2020 in seven out of the eight countries, with the biggest loss of trust in DRC, South Africa and Uganda. People in DRC, Kenya, Niger, Senegal and Nigeria thought that the Covid-19 vaccine was less effective in 2022 than they had expected it to be in 2020.
However, trust in the safety of the Covid-19 vaccine stayed consistent over the two years.
In 2022, the over-60s were more likely than younger adults to agree that vaccines are generally safe, effective and important for children, but no other links were found between vaccine confidence and sex, education, employment status or religious affiliation.
“Early warning signals of confidence losses, like those detected in this study, can provide time to respond, in the case of other epidemics, pandemics or other emerging crises,” said co-author, professor of Anthropology, Risk and Decision Science Heidi Larson, founding director of the Vaccine Confidence Project at LSHTM.
“Confidence monitoring at sub-national resolutions can also provide clearer signals to the regions and groups facing confidence losses and can better prepare policymakers and stakeholders for potential losses in vaccine uptake.”
A thorough investigation is now needed to find out whether loss of confidence in Covid-19 vaccines will trigger mistrust of other immunisation programmes, said the study authors.
“Considering global decreases in routine immunisation rates over the past two years, vaccine confidence losses could prove to be highly disruptive at this time when there are concerted efforts to address losses in routine immunisation rates post-pandemic.
“We need to understand the impact of the pandemic on confidence in routine immunisation programmes, not just in Africa, but across the world,” said De Figueiredo.
Declining trends in vaccine confidence across sub-Saharan Africa: a large-scale cross-sectional modelling study
A. de Figueiredo, E. Temfack, R. Tajudeen & H. Larson
Published in Human Vaccines & Immunotherapeutics on 9 May 2023
Current WHO/Unicef estimates of routine childhood immunisation coverage reveal the largest sustained decline in uptake in three decades with pronounced setbacks across Africa. Although the Covid-19 pandemic has induced significant supply and delivery disruptions, the impact of the pandemic on vaccine is less understood. We here examine trends in vaccine confidence across eight sub-Saharan countries between 2020 and 2022 via a total of 17 187 individual interviews, conducted via a multi-stage probability sampling approach and cross-sectional design and evaluated using Bayesian methods. Multilevel regression combined with post-stratification weighting using local demographic information yields national and sub-national estimates of vaccine confidence in 2020 and 2022 as well as its socio-demographic associations. We identify declines in perceptions toward the importance of vaccines for children across all eight countries, with mixed trends in perceptions toward vaccine safety and effectiveness.
We find that Covid-19 vaccines are perceived to be less important and safe in 2022 than in 2020 in six of the eight countries, with the only increases in Covid-19 vaccine confidence detected in Ivory Coast. There are substantial declines in vaccine confidence in the Democratic Republic of Congo and South Africa, notably in Eastern Cape, KwaZulu-Natal, Limpopo, and Northern Cape (South Africa) and Bandundu, Maniema, Kasaï-Oriental, Kongo-Central, and Sud-Kivu (DRC). While over 60-year-olds in 2022 have higher vaccine confidence in vaccines generally than younger age groups, we do not detect other individual-level socio-demographic associations with vaccine confidence at the sample sizes studied, including sex, age, education, employment status, and religious affiliation. Understanding the role of the Covid-19 pandemic and associated policies on wider vaccine confidence can inform post-Covid vaccination strategies and help rebuild immunisation system resilience.
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