Cutting coronavirus infectivity period by half a day could prevent 1.4 million cases in US alone, study suggests

Alexandra Thompson
·4-min read
medication for treatment corona virus infection(COVID-19,novel coronavirus disease 2019)
Coronavirus drug development should also focus on treatments that cut the period of infectivity, research suggests. COVID-19 is the disease caused by the coronavirus.

A drug or vaccine that cuts the coronavirus’ infectivity period by half a day could save 1.4 million cases in the US alone, research suggests.

In June, NHS hospitals started administering the low-cost steroid dexamethasone to patients on ventilators, after scientists from the University of Oxford reported it could reduce the risk of death by a third.

The UK has also approved two coronavirus vaccines to date, however, research only demonstrates they lower the risk of complications, rather than transmission.

With calls for more treatments to combat the pandemic, scientists from the CUNY Graduate School of Public Health and Health Policy in New York ran a computer model that simulated the spread of the coronavirus.

Read more: How concerning is the South African coronavirus variant?

Results suggest cutting its contagious period by half a day could prevent up to 1.4 million cases and more than 99,000 hospitalisations in the US alone.

Reducing the contagious period by 3.5 days was found to avert up to 7.4 million cases.

Young woman wearing surgical mask in front of home
Face coverings may be required in public enclosed spaces until a sufficient number of people have been vaccinated or an effective coronavirus drug is widely available, officials have previously said. (Posed by a model, Getty Images)

“There may be a tendency to overlook vaccines and other treatments that don’t prevent a COVID-19 [the disease caused by the coronavirus] infection or cure disease,” said lead author Professor Bruce Lee.

“But this study showed even relatively small changes in how long people are contagious can significantly affect the transmission and spread of the virus, and thus save billions of dollars and avert millions of new cases.”

Studies have thrown up mixed results when it comes to the coronavirus’ infectivity period, with the length of time varying between individuals.

Read more: Should the second coronavirus vaccine dose be delayed?

People with symptoms who test positive for the infection should self-isolate for 10 days from when the tell-tale fever, cough, or loss of taste or smell start, according to the NHS.

Asymptomatic people should self-isolate for 10 days from the positive test.

While symptoms usually ease during this time, anyone with a persistent fever, runny nose, sneezing, nausea, vomiting or diarrhoea should continue to stay at home until after these have passed.

Not everyone who tests positive for the coronavirus develops symptoms, however, making isolation complex.

The CUNY team’s simulations suggest that even if just a quarter of people with coronavirus symptoms were treated with an infectivity-cutting drug, up to 1.4 million cases of the infection could be prevented.

This is based on the basic reproduction number (R) being 2.5. R describes the number of people a patient is expected to pass the virus on to, in this case 2.5 individuals.

R fluctuates according to the restrictions that are in place, as well as the proportion of the public that has been vaccinated or overcome the infection naturally.

Reduced hospitalisations would also save $209.5bn (£154.1bn) in medical costs, according to results published in the journal PLOS Computational Biology.

This is based on “conservative estimates of how contagious the virus may be”, stressed the scientists.

Treating 75% of symptomatic coronavirus patients with such a drug would save 2.8 million future cases, the results suggest.

Read more: Stroke-like brain damage found in coronavirus victims

If the medication cut the infectivity period by 3.5 days, treating a quarter of symptomatic patients could prevent 7.4 million cases.

The scientists hope their results will help guide research and investments into the development of new coronavirus vaccines or drugs.

“This study shows vaccine and medication development efforts for COVID-19 should focus on the impact to actually help curb the spread of the COVID-19 pandemic, not just benefits of a single patient,” said co-author Dr James McKinnell, from research centre The Lundquist Institute in California.

“Widespread treatment, in combination with other prevention efforts, could prove to be the tipping point.”

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