Influenza-like illness surveillance reveals spike in undetected COVID-19 cases in March

June 22, 2020

A surge in flu-like infections in the U.S. in March of 2020 suggests that the likely number of COVID-19 cases was far larger than official estimates, according to a new study of existing surveillance networks for influenza-like infections (ILIs). The findings support a scenario where more than 8.7 million new SARS-CoV-2 infections appeared in the U.S. during March, and estimate that more than 80% of these cases remained unidentified as the outbreak rapidly spread. Furthermore, the results suggest that surveillance networks for influenza-like disease offer an important tool to estimate the prevalence of COVID-19, which has been hard to pin down. Many scientists suspect that the true rate of SARS-CoV-2 infections is higher than the number of confirmed cases due to the low availability of testing and because some infected individuals show no symptoms or only mild flu-like symptoms. Using an outpatient surveillance system for diseases with symptoms that resemble influenza, Justin Silverman and colleagues determined the prevalence of non-influenza ILIs in the U.S. annually using surveillance data starting from 2010. In March of 2020, they observed a huge spike in ILIs exceeding normal seasonal numbers in various states - New York, for example, showed twice its previous record for ILIs in the fourth week of March. The authors also saw that the dynamics of non-influenza ILIs closely matched patterns of confirmed COVID-19 cases. After calculating that approximately 32% of people infected with SARS-CoV-2 sought medical care, Silverman et al. found that at least 8.7 million SARS-CoV-2 infections occurred between March 8 and March 28 in the U.S., with new deaths doubling approximately every 3 days. The team concludes that the initial spread of COVID-19 therefore included a large undiagnosed outpatient population who potentially showed milder symptoms compared with those who were hospitalized.

American Association for the Advancement of Science

Related Infections Articles from Brightsurf:

Understanding the progress of viral infections
A team of researchers at the Institute for the Genetics of Heart Diseases at M√ľnster University created a viral expression model that can be used to simulate and analyse a large number of viral infections - including the one with SARS-CoV-2.

How viral infections associated with cancer become persistent?
A new study led by Pedro Simas, group leader at Instituto de Medicina Molecular (iMM; Portugal) and Kenneth M.

New drug formulation could treat Candida infections
With antimicrobial resistance (AMR) increasing around the world, new research led by the University of Bristol has shown a new drug formulation could possibly be used in antifungal treatments against Candida infections.

A 'shocking' new way to treat infections
New research from the University of Pittsburgh's Swanson School of Engineering introduces a revolutionary treatment for these infections.

Young infants with fever may be more likely to develop infections
Infants with a high fever may be at increased risk for infections, according to research from Penn State College of Medicine.

Hospital infections declining in Canada
There is good news on the infection front: infections acquired by patients in Canadian hospitals are declining, with a 30% reduction between 2009 and 2017, according to new research in CMAJ (Canadian Medical Association Journal).

Helminthic infections may be beneficial against HIV-1
Infection with parasitic helminths can reduce the susceptibility of T-cells to HIV-1 infection, according to a study published Sept.

Waking up sleeping bacteria to fight infections
Researchers in the group of Jan Michiels (VIB-KU Leuven Center for Microbiology) identified a mechanism of how sleepy bacteria wake up.

Typhoid vaccine may protect against other infections
New research by the University of Liverpool and Liverpool School of Tropical Medicine shows that vaccination with weakened strains of Salmonella may also protect against other infections.

New AI can detect urinary tract infections
New AI developed at the University of Surrey could identify and help reduce one of the top causes of hospitalisation for people living with dementia: urinary tract infections (UTI).

Read More: Infections News and Infections Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to