Frequent and rapid testing can control Covid-19 infection within weeks: Research-World News

A new study shows that weekly testing of half of the population with the cheap and fast turnaround Covid-19 test eliminates the pandemic within weeks, even if the test is significantly less sensitive than the gold standard clinical diagnosis. can do. According to a study published in the journal Science Advances, such a strategy could lead to a “personal curfew” without closing restaurants, bars, retail stores and schools.

According to scientists, including scientists at the University of Colorado at Boulder in the United States, the sensitivity levels of the various types of Covid-19 tests currently in use around the world vary widely. Antigen tests require a relatively high viral load (about 1,000 times more virus than PCR tests) to detect infection, they said.

Another test, known as the RT lamp, can detect about 100 times more virus than PCR, the study says. Scientists added that benchmark PCR tests require only 5,000 to 10,000 copies of viral genetic RNA per milliliter of sample. This means that you can catch the virus very quickly or very late.

“Our big picture is that when it comes to public health, a less sensitive test with today’s results is better than a more sensitive test with tomorrow’s results,” said a researcher at the University of Colorado at Boulder. Author Daniel Laremore said. America.

“Rather than telling everyone to stay home and preventing even one sick person from spreading it, ordering only infectious people to stay home and others You can be able to live your life, “says Larremore. ..

In this study, scientists evaluated whether test sensitivity, frequency, or turnaround time was of paramount importance in controlling the Covid-19 epidemic.

They analyzed the available literature on how viral load rises and falls in the body during infection, when people tend to experience symptoms, and when they are transmitted.

Scientists used mathematical modeling to predict the impact of screening with different types of tests on three virtual scenarios (10,000 people). In a college-type setting of 20,000 people; and in 8.4 million cities.

They found that frequency and turnaround time were far more important than test sensitivity when it came to limiting spread.

Citing a fictitious example, researchers said that quick, insensitive tests twice a week in large cities reduced virus infection by 80%. However, the study found that a twice-weekly test using a more sensitive PCR test, which took up to 48 hours to return results, reduced infectivity by only 58%. He states that for the same amount of tests, rapid tests are always less infectious than slower, more sensitive PCR tests.

Scientists explained that this is because about two-thirds of infected people are asymptomatic and continue to spread the virus while waiting for results. “This treatise is one of the first to show that frequency and turnaround should be prioritized when it comes to public health, without having to worry about test sensitivity,” said the Howard Hughes Medical Institute in the United States. The lead author of the study, Roy Parker, said.

Researchers believe that the findings show the power of frequent tests to shorten the pandemic and save lives.

In a scenario where 4% of individuals in a city are already infected, a rapid test of 3 out of 4 people every 3 days reduces the number of people eventually infected by 88%, “extinct the epidemic. Enough to drive them away. ” Six weeks. “These rapid tests are infectious tests. They are very effective at detecting Covid-19 when people are infected,” said Michael Mina, another co-author of the Harvard School of Public Health in the United States. Stated.

Some rapid tests can return results in 15 minutes, but PCR tests can take days.

“Within a few weeks, we were able to see this outbreak change from a huge number of cases to a very manageable level,” Mina said.

Researchers believe it’s time to change the Covid-19 testing strategy from what is available to people with symptoms to what it considers to be an important tool for breaking the transmission chain.