Vaccination and Measles Epidemic in the Republic of Congo

Léa Gwladys Gangoue^1,2, Yanne Mavougou^1,2, Fabien Rock Niama^1,2, Pembe Issamou Mayengue^1,2, Etienne Nguimbi²

¹National Public Health Laboratory (LNSP), Ministry of Health and Population, Brazzaville, Republic of Congo.
²Cellular and Molecular Biology Laboratory (BCM), Faculty of Sciences and Techniques, Marien Ngouabi University, Brazzaville, Republic of Congo.

DOI: 10.4236/ojepi.2024.141004                

Abstract

Measles is a highly infectious, vaccine-preventable viral disease. Often forgotten, it is potentially fatal. Its main symptoms are: fever, cough, conjunctivitis, rhinitis and skin rash. Serological diagnoses by ELISA test based on the detection of anti-measles virus immunoglobulins M and G (IgM and IgG), are used respectively for the confirmation of suspected cases notified by means of clinical signs of the disease in health structures of the twelve departments of the Republic of Congo involved in the epidemiological surveillance of the disease, and for the evaluation of the immunity conferred by vaccination. During 2021, 459 suspected cases of measles were reported and sampled throughout the country, despite the administration under the Expanded Routine Immunization Program (EPI), of 2 doses of the combined measles-rubella vaccine (RR1 and RR2) in 2020. The notification rate was higher in the south of the country, more precisely in the health structures of the departments of Pointe-Noire (42%) and Brazzaville (11%). During the year 2021, 459 suspected cases of measles were notified and sampled throughout the country with a high notification rate in the south of the country, more precisely in the health structures of the Pointe-Noire departments (42%) and Brazzaville (11%). The samples consisting of human blood (serum) were sent to the National Public Health Laboratory and analyzed by various ELISA tests for the detection of anti-measles immunog-lobulins M and G. The analysis of the results obtained shows that the measles virus circulated in all departments of the country. 154 cases (33.55%) were confirmed positive by IgM ELISA and 98 positive cases (63.63%) were patients vaccinated against measles. Vaccination coverage in RR1 of [50%-95% [(first dose) as well as the lowest RR2 < 50% (second dose) undoubtedly because the COVID-19 pandemic could be the cause of the high frequency of cases positive vaccinated. The non-detection of IgG immunoglobulins in vaccinated patients observed by IgG ELISA tests revealed that 63.26% of vaccinated patients were not immunized against the measles virus. These results confirm those obtained during the Elisa IgM analysis and make it possible to deduce that the quality, the number of doses not properly administered, the individual characteristics of the people as well as the poor conservation of the administered vaccine (non-compliance with the cold chain) would explain the high proportion of positive cases of vaccinated measles observed.

Keywords

Vaccination , Measles Epidemic

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.

References

[1]	Strebel, P.M. and Orenstein, W.A. (2019) Measles. The New England Journal of Medicine, 381, 349-357. https://doi.org/10.1056/NEJMcp1905181
[2]	Bhattacharjee, S. and Yadava, P.K. (2018) Measles Virus: Background and Oncolytic Virotherapy. Biochemistry and Biophysics Reports, 13, 58-62.
[3]	WHO (2017) Weekly Epidemiological Record/Measles Vaccines: WHO Position Paper. 92, 205-228. https://www.who.int/publications/journals/weekly-epidemiological-record
[4]	World Health Organization (2019) Measles. https://www.who.int/en/news-room/fact-sheets/detail/measles
[5]	WHO (2023) Measles. https://www.who.int/news-room/fact-sheets/detail/measles
[6]	Dendasck, C.V.,et al. (2023) Analyse quantitative et épidémiologique des cas de rougeole à Macapá-AP de 2017 à 2021. Revista Científica Multidisciplinar Núcleo do Conhecimento, 1, 93-106.
[7]	Mortamet, G., Dina, J., Freymuth, F. and Guilois, B. (2012) Measles in France. Arch Pediatric, 19, 1269-1272. https://doi.org/10.1016/j.arcped.2012.08.006
[8]	European Centre for Disease Prevention and Control (2022) Measles Annual Epidemiological Report. Surveillance Report. https://www.ecdc.europa.eu/sites/default/files/documents/Measles%20Annual%20Epidemiological%20Report%202022%20data.pdf
[9]	Boutoto, A. (2009) Epidemiological Surveillance of Measles in Brazzaville, Republic of Congo. Master’s Thesis, The Jean Joseph Loukabou Paramedical School of the Brazzaville University Hospital Center (CHU-B), Brazzaville.
[10]	(2023) Measles: Questions and Answers Information about the Disease and Vaccines. https://www.immunize.org/wp-content/uploads/catg.d/p4209.pdf