A new study has found that during the initial wave of the COVID-19 outbreak in New York City, only 1 in 5 to 1 in 7 cases of the virus was symptomatic. The research team found that non-symptomatic cases substantially contribute to community transmission, making up at least 50% of the driving force of SARS-CoV-2 infection. The results were published in the Proceedings of the National Academy of Sciences.
When the COVID-19 epidemic arrived in the U.S., the investigators noticed that it was very difficult to estimate what proportion of people infected with SARS-CoV-2 would go on to develop symptoms, partially due to the initial challenges with testing capacity.
"Without testing capacity data, it's very difficult to estimate the difference between cases that were unreported due to a lack of testing and cases that were actually asymptomatic," said first author. "We wanted to disentangle those two things, and since New York City was one of the first cities to report the daily number of tests completed, we were able to use those numbers to estimate how many COVID-19 cases were symptomatic."
While there are a number of existing models that use epidemiological data to estimate undetected case numbers and transmission rates, this is the first peer-reviewed model to incorporate data about daily testing capacity and changes in testing rates over time to provide a more accurate picture of what proportion of SARS-CoV-2 infections are symptomatic in a large U.S. city.
"Incorporating these data into the model showed that the proportion of individuals who are symptomatic for COVID-19 is somewhere between 13% and 18%," said senior author. "And regardless of uncertainty in all other parameters, we can tell that more that 50% of the transmission happening in the community is from people without symptoms ¬-- those who are asymptomatic and pre-symptomatic."
While this data analysis does not indicate how infectious asymptomatic individuals are, nor account for the new variants of the virus currently spreading in the U.S., the model provides additional support for the importance of following public health guidelines to reduce community transmission of the virus, whether individuals show symptoms.
"Even if asymptomatic people aren't transmitting the virus at high rates, they constitute something like 80% of all infections," said a co-author. "This proportion is quite surprising. It's crucial that everyone -- including individuals who don't show symptoms -- adhere to public health guidelines, such as mask wearing and social distancing, and that mass testing is made easily accessible to all."
The investigators say that these results also demonstrate that public health agencies need to make their testing protocols and numbers publicly available to allow these data to be incorporated into existing transmission models.
"Making this information available is as important as reporting the number of cases," said the senior author. "Otherwise, we have a discrepancy between the number and type of cases that are reported over time and the underlying transmission dynamics. These data are critical for epidemiological modeling."
https://www.pnas.org/content/118/9/e2019716118
http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fquantifying-asymptomatic&filter=22
At least 50% of COVID-19 infections come from people who aren't showing symptoms
- 1,517 views
- Added
Edited
Latest News
Role of alternative splicin…
By newseditor
Posted 27 Apr
How the brain fine-tunes it…
By newseditor
Posted 25 Apr
Immune cells carry a long-l…
By newseditor
Posted 25 Apr
Mutations in noncoding DNA…
By newseditor
Posted 24 Apr
More influence of environme…
By newseditor
Posted 24 Apr
Other Top Stories
Imaging Alzheimer's amyloid aggregates in the brain using copper
Read more
A small molecule reduces heart failure after myocardial infarction
Read more
Mitochondrial stress in astronauts!
Read more
Astrocytes increase pain sensitivity!
Read more
Signaling switch in pancreatic β-cells determines anti-diabetic dru…
Read more
Protocols
A programmable targeted pro…
By newseditor
Posted 23 Apr
MemPrep, a new technology f…
By newseditor
Posted 08 Apr
A tangible method to assess…
By newseditor
Posted 08 Apr
Stem cell-derived vessels-o…
By newseditor
Posted 06 Apr
Single-cell biclustering fo…
By newseditor
Posted 01 Apr
Publications
IL-6 promotes tumor growth…
By newseditor
Posted 27 Apr
Partial loss of MCU mitigat…
By newseditor
Posted 27 Apr
Thiol dioxygenases: from st…
By newseditor
Posted 27 Apr
Systematic characterization…
By newseditor
Posted 27 Apr
The MYCN 50 UTR as a therap…
By newseditor
Posted 25 Apr
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar