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. 2021 Jun 14;18(1):127.
doi: 10.1186/s12985-021-01594-0.

Influenza co-infection associated with severity and mortality in COVID-19 patients

Bandar Alosaimi  1 , Asif Naeem  2 , Maaweya E Hamed  3 , Haitham S Alkadi  2 , Thamer Alanazi  4 , Sanaa Saad Al Rehily  5 , Abdullah Z Almutairi  6 , Adnan Zafar  7
Affiliations

Influenza co-infection associated with severity and mortality in COVID-19 patients

Bandar Alosaimi et al. Virol J. .

Abstract

Background: In COVID-19 patients, undetected co-infections may have severe clinical implications associated with increased hospitalization, varied treatment approaches and mortality. Therefore, we investigated the implications of viral and bacterial co-infection in COVID-19 clinical outcomes.

Methods: Nasopharyngeal samples were obtained from 48 COVID-19 patients (29% ICU and 71% non-ICU) and screened for the presence of 24 respiratory pathogens using six multiplex PCR panels.

Results: We found evidence of co-infection in 34 COVID-19 patients (71%). Influenza A H1N1 (n = 17), Chlamydia pneumoniae (n = 13) and human adenovirus (n = 10) were the most commonly detected pathogens. Viral co-infection was associated with increased ICU admission (r = 0.1) and higher mortality (OR 1.78, CI = 0.38-8.28) compared to bacterial co-infections (OR 0.44, CI = 0.08-2.45). Two thirds of COVID-19 critically ill patients who died, had a co-infection; and Influenza A H1N1 was the only pathogen for which a direct relationship with mortality was seen (r = 0.2).

Conclusions: Our study highlights the importance of screening for co-infecting viruses in COVID-19 patients, that could be the leading cause of disease severity and death. Given the high prevalence of Influenza co-infection in our study, increased coverage of flu vaccination is encouraged to mitigate the transmission of influenza virus during the on-going COVID-19 pandemic and reduce the risk of severe outcome and mortality.

Keywords: COVID-19; Co-infection; Influenza A H1N1; Mortality; SARS-CoV-2.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Frequency of coexistence of pathogens in COVID-19 patients. The figure shows the frequency of viral vs bacterial co-infections in COVID-19 patients. The number of viruses detected in 14 ICU patients was 9 (6 H1N1 and 3 Adenovirus) compared to 2 bacteria (1 Chlamydia pneumoniae and 1 Staphylococcus aureus) which indicates a higher likelihood of ICU admission with viral co-infection. In 34 non-ICU patients, 36 coexisting pathogens were detected namely 15 bacteria (12 Chlamydia pneumoniae and 3 Staphylococcus aureus) and 21 viruses (11 H1N1, 7 Adenovirus, 1 metapneumovirus, 1 parainfluenza-3, and 1 influenza B) although none of them were involved in mortality
Fig. 2
Fig. 2
The binary fitted line plot shows the correlation between age and the probability of ICU admission and co-infection among COVID-19 patients. (A) The probability of an admission into the ICU among different age groups revealed an increasing trend with aging. (B) The probability of detection of a coinfection also exhibited a moderate linear correlation with age
See this image and copyright information in PMC

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