The bottom line: Frequency of co-infections in adults is unknown, but evidence from case reports and case series suggests that they do occur.
Strength of evidence: Limited data from case reports and case series
Discussion: We will break down the results of the individual data sources (that we are aware of) addressing this question below. Please comment on this post or email us if you are aware of other studies that we should evaluate.
Case report from China-Japan Friendship Hospital (1): A 69yo man with recent travel to Wuhan presented with fever and dry cough. CT-chest showed RLL ground glass. PCRs from nasopharyngeal swabs using different assays were negative for SARS-CoV2 but positive for influenza A. PCRs from nasopharyngeal and sputum samples on day 7 was negative for SARS-CoV2 too. He developed worsening hypoxia and lymphopenia and CT abnormalities progressed to involve both lungs. On day 11, a bronchoscopy was performed. They performed next-generation sequencing and identified SARS-CoV2, so they performed PCRs on nasopharyngeal, sputum, and BAL samples. PCR from the day 11 sputum and BAL sample were positive for SARS-CoV2, but the PCR from a nasopharyngeal swab collected at the same time was negative. This report supports the hypothesis that other respiratory viruses co-occur with SARS-CoV2 in adults (and that it may be subtle to detect). Although the findings are suggestive and the report has been published in a peer-reviewed journal, the level of evidence (case report) is not strong and needs to be substantiated by other studies.
Case series from Wuhan Childrens Hospital (2): Among n=20 pediatric inpatients (median age 2 years, 1.5 months), co-infection with “other pathogens” (including influenza viruses A and B, mycoplasma, respiratory syncytial virus, and cytomegalovirus) occurred in 40% (8/20). The methods used to ascertain co-infection were not reported but appear to include more than just PCRs for other respiratory viruses. Results for individual co-infecting pathogens are not provided. There are important limitations in this case series for application to adult populations, most notably the young age of the individuals studied. Also, because they do not report the numbers of individual co-infections or the assays used, it is difficult to know estimate many of the co-infections would have been detected by using a routine respiratory viral panel.
Stanford Medicine Data Scientists report on medium.com: Out of 562 individuals tested for both SARS-CoV2 and other respiratory viruses (for Flu A/B/RSV or a broader respiratory panel), 22.6% (n=127) were positive for other viruses, most commonly rhinovirus/enterovirus (which can persist for a long time after infection). Looking at it from the angle that may be of most interest to clinicians deciding whether a SARS-CoV2 panel is indicated, for individuals who tested positive for other viruses, approximately 9% (11 out of 127), also tested positive for SARS-CoV2. There are important limitations in this case series. First, this report has not been peer-reviewed. Second, no information on clinical characteristics is presented. Last, and most importantly, although the average age of participants studied is not stated, some of the investigators are pediatricians, and these results may not be generalizable to adult populations.
Authors: Pandora “Luke” Wander, MD, MS, FACP
URLs:
https://wwwnc.cdc.gov/eid/article/26/6/20-0299_article
https://onlinelibrary.wiley.com/doi/10.1002/ppul.24718
https://medium.com/@nigam/higher-co-infection-rates-in-covid19-b24965088333
Date last reviewed: 3/20/20
Disclaimer: The opinions expressed are the writers’ alone and do not reflect those of our parent institutions. The information here is designed to provide helpful information on the subjects discussed. It is not meant to diagnose, treat, or prevent and medical condition. We disclaim any liability in connection with the use of this information.
References:
1. Wu X, Cai Y, Huang X, Yu X, Zhao L, Wang F, Li Q, Gu S, Xu T, Li Y, Lu B, Zhan Q: Co-infection with SARS-CoV-2 and Influenza A Virus in Patient with Pneumonia, China. Emerg Infect Dis 2020;26
2. Xia W, Shao J, Guo Y, Peng X, Li Z, Hu D: Clinical and CT features in pediatric patients with COVID-19 infection: Different points from adults. Pediatr Pulmonol 2020;