Discussion
This work highlights that 6% of SARS-CoV-2-infected patient presented
with viral co-infection at our adult ED. This proportion is higher than
previously reported for SARS-CoV-2 [6] but at a level similar to the
other respiratory viruses[12]. This high prevalence of viral
co-infections was observed, despite the limited circulation of other
respiratory viruses due to lockdown, curfew, and being in the tail of
the season of respiratory viruses [7]. Rhinoviruses, adenoviruses,
and other coronaviruses were the most frequently detected viruses with
SARS-CoV-2. Adenoviruses and rhinoviruses have already been reported,
outside the scope of SARS-CoV-2, as being more frequently involved in
viral co-infection, contrary to influenza viruses [13].
In our population, only 6 patients with SARS-CoV-2 were also infected
with atypical bacteria. Co-infections can lead to viral interference,
one virus limiting or suppressing the replication of the second virus,
or to an enhancement of disease severity compared to mono-infection
[14]. In our cohort, patients presenting with viral co-infections
with SARS-CoV-2 had similar clinical pictures, except for headache and
fever, and prognosis than patients solely infected with SARS-CoV-2.
Our study presents several strengths and limitations. It showed a
relatively large number of SARS-CoV-2 co-infections compared to previous
works [4–7] and linked virological data with detailed clinical
data. Syndromic mPCR testing was performed on all patients presenting
with ILI during the study period. Thus patients recruited in this
observational study are not skewed towards more severe patients and
represent all adult patients hospitalised for ILI. However, our study is
monocentric, and the SARS-CoV-2 epidemic flared in Ile-de-France when
the incidence of most respiratory viruses was waning. Prevalence of
viral co-infections with SARS-CoV-2 might be higher in settings with an
active circulation of respiratory viruses and/or once social distancing
will be over. We also cannot rule out that some specific co-infections
might have a deleterious impact, notably SARS-CoV-2/influenza, as only 4
were detected during our study period. Higher severity of
SARS-CoV-2/influenza A H1N1pdm2009 has recently been described in golden
Syrian hamsters when the two viruses were simultaneously inoculated
[15]. We also did not retrieve data on the other pneumonia diagnosis
related to pneumococcus or staphylococcus . Thus, although
we found that SARS-CoV-2 viral co-infections were rare during the first
epidemic wave and did not differ either by their clinical presentation
or their outcome from SARS-CoV-2 mono-infections, this reassuring
finding must be confirmed in the upcoming months.
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