Introduction since 1971, Cameroon is facing a growing series of cholera epidemics despite all the efforts made by the government to address this huge public health threat. In 2020, in addition to the COVID-19 pandemic, Cameroon recorded a high cholera case fatality rate of 4.3% following epidemics noted in the South, Littoral and South-West regions. The Cameroon Ministry of Public Health, has thus organized a reactive vaccination campaign against cholera to address the high mortality rate in the affected health districts of those regions. The objective of this study was to describe the challenges, best practices and lessons learned drawing from daily experiences from this reactive vaccination campaign against cholera. Methods we conducted a cross-sectional study drawn from the results of the campaign. We had a target population of 631,109 participants aged 1 year and above resident of the targeted health areas. Results the overall vaccination coverage was 64.4% with a refusal rate ranging from 0-10% according to health districts. Vaccination coverage was the lowest among people aged 20 years and above. The main challenge was difficulty maintaining physical distanciation, the main best practice was the screening of all actors taking part at the vaccination against COVID-19 and we found that emphasizing on thorough population sensitization through quarter heads and social mobilizers and adequately programming the campaign during a good climate season is crucial to achieving good vaccination coverage. Conclusion lessons learned from this study could serve to inform various agencies in the event of planning rapid mass vaccination programs during pandemics.

Introduction There have been public health concerns about a potential association between human papillomavirus (HPV) vaccines and premature ovarian failure (POF) in young women. Objective To identify a potential safety signal of POF after HPV vaccination using the United States (US) Vaccine Adverse Event Reporting System (VAERS) database. Methods We manually selected relevant MedDRA preferred terms related to POF and identified in VAERS all POF reports in women less than 40 years of age between 2 July 1990 and 14 May 2018, followed by a review of narratives to confirm the cases. We conducted descriptive analyses on age, POF type, HPV vaccine type (HPV2, HPV4, HPV9), time to onset of POF, and dose rank. We described trends in reporting over time and assessed a potential safety signal using the proportional reporting ratio (PRR). Results Of the 228,341 eligible POF reports, 281 (0.1%) were suspected to be associated with HPV vaccines. Median patient age was 15 years (range 11-39 years). POF events consisted mainly of amenorrhea (80.4%) and premature menopause (15.3%). Mean number of reported POF events significantly increased after the first HPV vaccine launch in 2006 with 22.2 POF cases/year up from 1.4 POF cases/year before the launch. PRR was 46.1 (95% confidence interval: 31.7-67.2) and sensitivity analyses yielded similar estimates. Conclusion Our study suggests the presence of a potential safety signal of POF associated with HPV vaccination, which may only be partly attributed to notoriety bias. Due to the well-known limitations of spontaneous reporting data, further investigations are warranted.

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