Risk Factors for Influenza Disease in Shai-Osudoku and Ningo-Prampram Districts in the Greater Accra Region of Ghana

Aims: This study sought to determine the risk factors of Influenza by investigating the characteristics of patients with Acute Respiratory Infections (ARIs).

Study Design: An unmatched case-control study.

Place and Duration of Study: This was conducted among residents of Shai-Osudoku (SO) and Ningo-Prampram (NP) Districts from April to November 2016.

Methods: Prospective cases of ARIs from a facility-based sentinel surveillance on respiratory illnesses were screened for Influenza-Like-Illnesses (ILIs). Respiratory samples were obtained from those meeting the case definition for ILI and investigated. A total of 147 samples were influenza virus-positive and selected as case-patients. Another 294 patients were selected as control-patients from the pool of influenza negative tests. These two groups were used to assess the risk factors of influenza. Crude and adjusted odds ratios were calculated. A purposive selection logistic regression was used for the adjusted modelling.

Results: The study identified Influenza A(H3N2) and Influenza B as the predominant circulating influenza viruses. Study participants had poor knowledge on the causes and prevention of acute respiratory illness. After the multivariate analysis, ILI patients presenting with Chills had 4 times odds (aOR:4.57; 95%CI: 1.51 – 13.76) of having influenza as compared with the controls. In addition, ILI patients with recent travel history in past 2 weeks had 3 times odds (aOR:3.05; 95%CI: 1.07 – 8.73) of being infected with the influenza virus compared with controls with no history of travel.

Conclusion: The study provided clues for increasing the index of suspicion of clinicians in identifying patients with respiratory signs who could be at risk of influenza infection. Communication of the significant risk factors identified in the study to all health workers should be prioritized as an action. This important knowledge about factors associated with influenza among ILIs will inform early detection and appropriate health interventions to reduce the burden influenza disease.