Influenza a and COVID-19 Coinfection: A Systematic Review of Cases

Our systematic review summarises the evidence on COVID-19 patients co-infected with Influenza A (IFV-A). We searched PubMed, Cochrane library, and Google scholar databases from December 1, 2019, till August 24, 2021. From an initial 881 studies, 32 studies provided specific information on COVID-19-IFV-A co-infection. Studies described 335 patients, 53.7% were female and the mean age was 59.08 years. The most common comorbidities in COVID-19 patients co-infected with IFV-A were hypertension (32.4%) and diabetes mellitus (21.6%). Fever (78.2%), cough (45.7%), and dyspnoea (28.1%) were the main symptoms in COVID-19-IFV-A co-infection, which are also common in COVID-19 and IFV-A alone. 95.04% of the patients reported abnormal radiological findings with ground-glass opacities being the most widely reported finding (62.41%). Also, the most common laboratory findings were lymphopenia (41.5%) and elevated C-reactive protein (47.2%). PCR (28/28 studies) and NAA (18/28 studies) were the most popular diagnostic methods for COVID-19 and IFV-A, respectively. Moreover, Oseltamivir was the most prescribed drug (62.5%), followed by Azithromycin (17.5%). Poor prognosis was reported for a significant 10.9% of the patients. Our findings indicate that COVID-19-IFV-A co-infection could lead to a more severe condition, especially in the elderly or in patients with comorbidities. Thus, the vulnerable population should take appropriate mitigation measures like vaccination to protect themselves from disease altogether and physicians should pay more attention to patients with COVID-19-IFV-A co-infection.Funding Information: This study was not funded.Conflict of Interests: The authors declare that they have no competing interests.