Discussion
Viruses co-infection were usually seen in the influenza epidemic and
pandemic (Goka, Vallely, Mutton, & Klapper, 2013;Meskill, Revell,
Chandramohan, & Cruz, 2017). Goka et al found that IAV and influenza B
virus co-infection was associated with a significant increase in risk of
admission to ICU or death, whereas co-infection with IAV and other
viruses significantly increased the risk of admission to a general ward
(Goka et al, 2013). In the COVID-19 pandemic, we found some patients
were co-infected with SARS-COV-2 and IAV but we did not know much more
about the two viruses’ co-infection. To better understand the clinical
course of
SARS-COV-2
and IAV co-infection, we performed a fast review on patients infected
with the two viruses.
In this review, we collected 13 patients co-infected with SARS-COV-2 and
IAV in China, Japan, Iran and America (Azekawa et al, 2020;Ding et al,
2020;Khodamoradi et al, 2020;Konala et al, 2020;Sha, 2020;Wu et al,
2020). In the 13 patients, the propotion of sever type was 53.8% (7
cases), which was much higher than that in COVID-19 (Guan et al, 2020),
indicating co-infection with SARS-COV-2 and IAV resulting in more severe
condition. IAV infection was more common in children and old people
(Thompson, 2004), while we only found one child suffering from
SARS-COV-2 and IAV co-infection in our cohort (Sha, 2020). Similar to
the COVID-19 patients, the patients co-infected with SARS-COV-2 and IAV
also manifested symptoms such as fever, cough, dyspnea and myalgia etc.
However, in this review, we found 10 of 13 patients (76.9%) had dyspnea
on admission, higher than that reported by Wang and Huang et al (31.2%
and 55% respectively) (Huang et al, 2020;Wang et al, 2020). This may
remind us that COVID-19 patients co-infected with IAV may develop a more
severe disease in lower respiratory tract. The median time of hospital
stay in this review was 17 days (IQR,15-20), similar to the finding
(median, 18 days, IQR, 14-27) reported by Xu et al (Xu et al, 2020). The
reason why patients co-infected with SARS-COV-2 and IAV developed more
severe clinical condition while had similar hospital stay need further
research. All the patients had typical abnormal radiological changes and
7 of 13 patients (53.8%) had lower lymphocyte count on admission, which
could indicate viral infection but could not tell the pathogens relying
on these signs.
In this review, we found 8 of 9 patients (88.9%) were treated with
oseltamivir,
a neuraminidase inhibitor recommended to deal with influenza by the
European Union and the USA(European Centre For Disease Control, 2017;
Centers for Disease Control and Prevention), and 8 of 8 patients
received antibiotic therapy to
prevent secondary bacterial infection(McCullers & Bartmess, 2003). But
whether oseltamivir has some effect on SARS-COV-2 viral shedding and
whether co-infection with SARS-COV-2 and IAV will cause secondary
infection need further investigation. Three patients were treated with
corticosteroids,
while
corticosteroids were not usually recommended
in the COVID-19 pandemic
concerning about the possible side effects of corticosteroids on virus
clearance and association with high rates of complications (Arabi et al,
2018;Stockman, Bellamy & Garner, 2006). 7 patients were cured and
discharged from hospital while 6 patients did not have detailed
information on clinical course.
We noticed the patients co-infected with SARS-COV-2 and IAV accounted
for a small proportion in the COVID-19 pandemic (Kim, Quinn, Pinsky,
Shah, & Brown, 2020;Nowak, Sordillo, Gitman, & Paniz Mondolfi 2020).
This may due to the interference between viruses (Schultz-Cherry, 2015),
and SARS-COV-2 took the dominated place in the pandemic. The mechanism
of how SARS-COV-2 and IAV interfere each other deserves further study.
Our study has some limitations: first and most, though this was a fast
review, our samples were extremely small due to the rare reports on
SARS-COV-2 and IAV co-infection. Second, we could not collect detail
information about each patient because some information was not
available and whether the missing information may have some influence on
our results was unknown. Third, the reports did not provide SARS-COV-2
viral shedding time, thus whether co-infection with IAV have some
influence on SARS-COV-2 viral shedding remains unknown. Fourth, we could
not identify which virus was first infected, which may contribute to
account for the co-infection course. Finally, no patient got lower
respiratory tract samples for detection for SARS-CoV-2 and IAV in this
review, so whether the two viruses were both involved in the
pathological progression of pulmonary could not be identified. However,
this review highlights that we should pay attention to the problem of
co-infection of two or more respiratory pathogens. The association
between the occurrence of co-infection and substantially higher severity
of disease deserves further study, but
a
rapid and proper diagnostic of wide spectrum of viral respiratory
pathogens reveals an accurate picture of the disease and is essential
for appropriate therapeutic management and control of infection.