Shalom Tchokfe Ndoula

Cameroon introduced the human papilloma virus vaccine (HPVV) into the routine immunization schedule in October 2020. By the end of 2022, coverage remained low. To increase coverage, Cameroon switched to a country-wide, gender-neutral vaccination (GNV) approach in 2023, coupled with a revamped delivery strategy of Community Dialogues (CDs) and Periodic Intensification of Routine Immunization (PIRIs) activities in selected health districts (HDs). We assessed the impact of these programmatic changes, notably the GNV approach, on HPVV coverage. This retrospective, cross-sectional study measured the effect of GNV and CDs+PIRIs on HPVV coverage among 9-year-old girls in Cameroon (2022–2023). Data on HPV vaccination from all 203 HDs were extracted from DHIS2, and coveragecalculated at the HD level based on the estimated population eligible of 9-year-old girls. Descriptive statistics and multiple regression models were employed to assess the impact of GNV on vaccination coverage, while adjusting for CDs+PIRIs, baseline (2022) coverage, region, urban/rural status. In 2023, of the 203 HDs, 115 (56.7%) conducted GNV only and 74 (36.5%) implemented GNV & CDs+PIRIs. Among age-eligible girls, there was an overall increase in HPV vaccination coverage, with coverage rising 39.2 percentage points from 2022 to 2023. Following multiple linear regression, there was a significant association between percentage point increase in HPVV coverage in HDs with GNV & CDs+PIRIs, compared to those with no GNV and no CDs+PIRIs in the adjusted model (β:44.5, 95%CI: 29.4, 59.6, p < 0.001). Furthermore, there was a significant association between increase in HPVV coverage in HDs with GNV only compared to those with no GNV or no CDs+PIRIs in the adjusted model (β:15.5, 95%CI: 1.23, 29.8 p < 0.001). Overall, the GNV approach was associated with an increase in HPVV coverage for girls, with greater magnitude and predicted precision when implemented alongside CDs+PIRIs.

Background. From smallpox variolation practiced in imperial China in the 10th century to the messenger RNA vaccines deployed in 2020, vaccination ranks among the most effective public health interventions in the history of medicine. Nevertheless, the rare but clinically significant occurrence of serious adverse events following immunization (AEFI) remains a major challenge for contemporary pharmacovigilance. Identifying the individual determinants of susceptibility represents a leading scientific and ethical priority. Objective. To critically analyze the available scientific literature in order to determine the extent to which three families of host factors the HLA immunogenetic profile, undiagnosed mild immunodeficiencies, and chronic inflammatory comorbidities contribute to the occurrence of serious AEFI, and to identify biomarkers and prevention strategies likely to improve vaccine safety. Methods. Narrative and critical literature review. The PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar databases were searched for the period 1990–2025. Original articles, systematic reviews, meta-analyses, and case series describing a link between vaccination and HLA profiles, mild immunodeficiencies, or inflammatory comorbidities were included. Editorials without data and exclusively animal studies were excluded. Results. The data converge toward an integrative model in which serious AEFI result from the interaction between a platform-specific vaccine stimulus and a permissive host background. Certain HLA alleles (HLA-A*03:01, HLA-DRB1*11:04, HLA-DQB1*06) modulate antigen presentation and predispose to inadequate or autoreactive immune responses. Mild immunodeficiencies, particularly type I interferon deficits and dysregulation of regulatory T lymphocytes, compromise immune-braking mechanisms. Chronic inflammatory comorbidities, diabetes, hypertension, pre-existing autoimmune diseases raise the baseline level of inflammation and lower the threshold for triggering a pathological response. Four etiological categories of serious AEFI are identified: (A) with a dominant cause linked to the vaccine platform; (B) multifactorial metabolic; (C) mixed, resulting from the interaction between a vaccine mechanism and a latent host susceptibility; (D) with a mechanism not yet elucidated. Conclusion. The systematic integration of HLA typing, type I interferon assays, and cytokine profiling into pharmacovigilance algorithms would refine individual causal assessment and pave the way for personalized vaccination. Multicenter prospective studies, including African populations underrepresented in the literature, are needed to validate these biomarkers in clinical practice.

Cameroon introduced Human papilloma virus vaccine (HPVV) into the routine immunization schedule in October 2020. By the end of 2022, coverage remained low. To increase coverage, Cameroon switched to a country-wide, gender-neutral vaccination (GNV) approach in 2023, coupled with a revamped delivery strategy consisting of Community Dialogues (CDs) and Periodic Intensification of Routine Immunization (PIRIs) activities in selected health districts (HDs). We assessed the impact of these programmatic changes, notably the GNV approach, on HPVV coverage. This retrospective, cross-sectional study measured the effect of GNV and CDs + PIRIs on HPVV coverage among 9-year-old girls in Cameroon (2022-2023). Data on HPVV coverage from all 203 HDs were extracted from DHIS2, and coverage was calculated at the HD level, based on the estimated population eligible of 9-year-old girls. Descriptive statistics and multiple regression models were employed to assess the impact of GNV on vaccination coverage while adjusting for CDs + PIRIs and urban/rural status. In 2023, of the 203 HDs, 115 (56.7%) conducted GNV only, 74 (36.5%) implemented GNV & CDs + PIRIs, and 75.9% (154) were classified as rural. Among age-eligible girls, there was an overall increase in HPV vaccination coverage, with coverage rising 39.2 percentage points from 2022 to 2023. Following multiple linear regression, there was a significant increase in HPVV coverage in HDs with GNV & CDs + PIRIs compared to those with no GNV and no CDs + PIRIs (β:55.5%, 95%CI: 38.7, 72.3, p=0.000). Furthermore, there was a significant increase in HPVV coverage in HDs with GNV only compared to those with no GNV or no CDs + PIRIs (β:28.7%, 95%CI: 12.5, 45.0 p=0.001). Overall, the GNV approach increased HPVV coverage for girls significantly, particularly when implemented alongside CDs + PIRIs.

Background: Cameroon is the first country to introduce malaria vaccine (MV) into routine immunisation, following the pilot programme. The vaccine was introduced in 42 health districts across all 10 regions, with plans to scale up in additional districts in future. A mini-postintroduction evaluation (mini-PIE) was conducted to rapidly review the MV programme, make improvements and inform future strategies. Methods: A programme evaluation was conducted using desk review and field data collection with standardised interviews of immunisation staff and caregivers. A facilitated discussion was then conducted with key immunisation and malaria staff and partners using WHO intra-action review methodology. Results: The desk review found that completeness of monthly reports exceeded 95% in all regions in April 2024 except North-West and Adamawa (87%). Only 56% of eligible children received their first dose; however, coverage of the second and third doses was 31% and 28%, respectively. All 10 regions had high drop-out rates. Based on field data collection, 8 of 10 health facilities received communications materials for community awareness. Among caregivers interviewed, 88% (42/48) were aware of MV introduction (MVI); 60% (29/48) were informed by health workers and 81% (39/48) cited vaccine protection as the main reason to vaccinate children. 60% (29/48) knew the importance of continuing to use long-lasting insecticidal nets after malaria vaccination. During the facilitated discussion, 65% (n=37) of participants totally agreed that the mini-PIE methodology used was an effective way to identify challenges and lessons learnt. Conclusions: Cameroon’s MVI was largely successful, despite vaccine misinformation, demonstrating the importance of community dialogue and engagement in successful vaccine introduction. The mini-PIE methodology is recommended for other countries to adopt 4–6 months after introduction, including field work tailored to country needs and thorough desk review of key indicators conducted in advance to inform the facilitated discussion.

Background: Since 1974, Essential Programme on Immunisation managers from ten Central African countries meet yearly with partners to review progress made and share experiences and lessons learned from the implementation of immunization programmes. The 2024 meeting occurred in Kinshasa, Democratic Republic of Congo, in September 2024. This conference report summarizes the key takeaways from discussions on using immunization data for decision-making, the implementation of the Big Catch-Up (BCU) initiative to reduce the burden of zero-dose children, and progress and challenges in introducing selected new vaccines. Conference Takeaways: Inaccurate administrative data on routine immunization observed in most countries, compared to WHO/UNICEF Estimates of National Immunization Coverage and national survey estimates, affect timely decisions to improve the Expanded Programme on Immunization (EPI) performance. Five countries in Central Africa are among the priority countries of the BCU initiative but, as of the end of August 2024, are yet to formally start its implementation. Cameroon and Central African Republic introduced the malaria vaccine in January 2024 and August 2024, respectively, while the Democratic Republic of Congo, Chad, and Burundi have planned to do so by 2025. Conclusions and Recommendations: Meeting participants put forward several recommendations for countries and immunization partners, including but not limited to (i) investing more in routine immunization data quality assurance to better use data to inform decisions, (ii) accelerating the implementation of the BCU initiative to close the immunity gap resulting from routine immunization disruptions due to the COVID-19 pandemic, (iii) updating malaria vaccine introduction plans to invest more in demand generation and community engagement, and (iv) learning from Cameroon’s experience in tackling hesitancy to human papilloma virus vaccine. It is critical to set up an appropriate mechanism for monitoring the implementation of these recommendations.

Background: Little is known about attitudes towards COVID-19 vaccination in sub-Saharan Africa, where immunisation coverage is the lowest in the world. Aim: The study aimed to identify factors associated with COVID-19 vaccine hesitancy and uptake in Cameroon, and assess changes in these factors over a period of time. Setting: The study was conducted in the ten regions of Cameroon. Methods: The authors conducted a two-phase cross-sectional survey in the 10 regions of Cameroon, from July 2021 to August 2021 (Phase one) and from August 2022 to September 2022 (Phase two). We analysed reasons for vaccine hesitancy descriptively and used logistic regression to assess factors associated with hesitancy. Results: Overall, we enrolled 12 109 participants: 6567 (54.23%) in Phase one and 5542 (45.77%) in Phase two. Of these, 8009 (66.14%) were not interested in receiving the COVID-19 vaccine (n = 4176 in Phase one, n = 3833 in Phase two). The refusal rate increased significantly in the northern region from 27.00% in Phase 1 to 60.00% in Phase two. The leading contributor to COVID-19 vaccine hesitancy was fear that the vaccine was dangerous, which was significantly associated (95% confidence interval [CI], p < 0.05%) with vaccine refusal in both phases. Overall, 32.90% of participants (n = 2578) perceived the COVID-19 vaccine to be dangerous. Advanced age, male gender, Muslim religion and low level of education were associated with vaccine acceptance. Participants reported that healthcare workers were the most trusted source of information about the COVID-19 vaccine by 5005 (42.84%) participants. Conclusion: Despite the investment of the Ministry of Health and its partners in community engagement, focussing on communication about the vaccine efficacy, tolerance and potential adverse events, fear of the vaccine remains high, likely leading to vaccine hesitancy in Cameroon between 2021 and 2022. Contribution: The study highlight regional variations in COVID-19 vaccine acceptance in Cameroon, with factors age, gender, religion and education influencing willingness to vaccine. Trust in health workers was high, indicating that, tailored, community-led vaccination strategies are key for improving vaccine uptake, not only for COVID-19 but also for future epidemics.

Cameroon introduced the malaria vaccine in its routine immunization program on 22 January 2024 in the 42 districts out of 200 that are among the most at risk of malaria. A cross-sectional analysis of the data on key vaccine events in the introduction roadmap and the vaccine uptake during the first 30 days was conducted. In addition to available gray literature related to the introduction of the malaria vaccine, data on the malaria vaccine uptake by vaccination session, collected through a digital platform, were analyzed. A total of 1893 reports were received from 22 January 2024 to 21 February 2024 from 766 health facilities (84% of overall completeness). Two regions out of ten recorded less than 80% completeness. As of 21 February 2024, 13,811 children had received the first dose of the malaria vaccine, including 7124 girls (51.6%) and 6687 boys (48.4%). In total, 36% of the children were vaccinated through outreach sessions, while 61.5% were vaccinated through sessions in fixed posts. The overall monthly immunization coverage with the first dose was 37%. Early results have shown positive attitudes towards and acceptance of malaria vaccines. Suboptimal completeness of data reporting and a low coverage highlight persistent gaps and challenges in the vaccine rollout.

Cameroon introduced the malaria vaccine in its routine immunization programme on 22 January 2024, in the 42 districts out of 200, among the most at risk of malaria. A cross-sectional analysis of data on vaccine key events in the introduction roadmap and vaccine uptake during the first 30 days was conducted. In addition to available gray literature related to the introduction of the malaria vaccine, data on malaria vaccine uptake by vaccination session, collected through a digital platform, were analyzed. A total of 1,893 reports were received from 22 January 2024 to 21 February 2024 from 766 health facilities (85% of overall completeness). Two regions out of 10 recorded less than 80% of completeness. As of 21 February 2024, 13,811 children have received the first dose of the malaria vaccine, including 7,124 girls (51.6%) and 6,687 boys (48.4%). Thirty six percent of children were vaccinated through outreach sessions versus 61.5% through sessions in fixed posts. The overall monthly immunization coverage with the first dose was 37%. Early results have shown positive attitudes towards and acceptance of malaria vaccines. Suboptimal completeness of data reporting and low coverage highlight persistent gaps and challenges in vaccine rollout.