Effects of climatological parameters in modeling and forecasting seasonal influenza transmission in Abidjan, Cote d'Ivoire.

BACKGROUND: In temperate regions, influenza epidemics occur in the winter and correlate with certain climatological parameters. In African tropical regions, the effects of climatological parameters on influenza epidemics are not well defined. This study aims to identify and model the effects of climatological parameters on seasonal influenza activity in Abidjan, Cote d'Ivoire. METHODS: We studied the effects of weekly rainfall, humidity, and temperature on laboratory-confirmed influenza cases in Abidjan from 2007 to 2010. We used the Box-Jenkins method with the autoregressive integrated moving average (ARIMA) process to create models using data from 2007-2010 and to assess the predictive value of best model on data from 2011 to 2012. RESULTS: The weekly number of influenza cases showed significant cross-correlation with certain prior weeks for both rainfall, and relative humidity. The best fitting multivariate model (ARIMAX (2,0,0) _RF) included the number of influenza cases during 1-week and 2-weeks prior, and the rainfall during the current week and 5-weeks prior. The performance of this model showed an increase of >3 % for Akaike Information Criterion (AIC) and 2.5 % for Bayesian Information Criterion (BIC) compared to the reference univariate ARIMA (2,0,0). The prediction of the weekly number of influenza cases during 2011-2012 with the best fitting multivariate model (ARIMAX (2,0,0) _RF), showed that the observed values were within the 95 % confidence interval of the predicted values during 97 of 104 weeks. CONCLUSION: Including rainfall increases the performances of fitted and predicted models. The timing of influenza in Abidjan can be partially explained by rainfall influence, in a setting with little change in temperature throughout the year. These findings can help clinicians to anticipate influenza cases during the rainy season by implementing preventive measures.

Intent to receive flu vaccine and influenza vaccination coverage among health professionals during 2019, 2020 and 2021 campaigns in Côte d'Ivoire.

Vaccination of healthcare workers against influenza is a crucial strategy to reduce transmission amongst vulnerable populations, facilitate patient uptake of vaccination, and bolster pandemic preparedness. Globally, vaccination coverage of health workers varied from 10 % to 88 %. Understanding health workers' knowledge and acceptance of the influenza vaccine, particularly among physicians, is crucial for the fine-tuning and continued success of influenza vaccination campaigns. We conducted a cross-sectional survey of 472 health workers in Abidjan, Côte d'Ivoire, to inform subsequent subnational and national introductions of influenza vaccine and subsequent campaigns targeting health workers in 2019 (14302), 2020 (14872), and 2021 (24473). Using a purposive sample of university hospitals, general hospitals, rural, and urban health facilities, we interviewed a convenience sample of health workers aged 18 years and older. Physicians had the lowest intention to receive the influenza vaccine (58 %), while nurses (78 %) and midwives (76 %) were the most willing. Across all occupations, intention to receive vaccination increased if the vaccine was offered for free or if recommended by the Ministry of Health. 76 % of respondents believed that the influenza vaccine could prevent illness in health workers. Communication strategies, including about the benefits of influenza vaccination, could raise awareness and acceptance among health workers prior to vaccination campaigns. Influenza vaccination coverage rates between 2019 and 2021 were on par with rates of intention to receive vaccination in the 2018 survey; in 2019, 2020, and 2021, coverage among physicians was 73 %, 73 %, and 52 % and coverage among nurses and midwives was 86 %, 86 %, and 74 % respectively. Improving health workers' knowledge and acceptance of the influenza vaccine, particularly among physicians, is crucial for the continued success of influenza vaccination campaigns.