So warns a medical, British microbiologist based on extensive studies from around the world. She calls on decision-makers not to shorten the isolation and release to the environment people who may infect * Her findings are also relevant to Israel, which is about to adopt the procedure that began in the United States.
By Dr. Sally Coulter, Microbiologist, University of East London
Before the Omicron, people in the UK with corona symptoms or a positive test had to put themselves in ten-day isolation. But when the new strain arrived, the government changed the period of self-isolation to seven days. The U.S. Centers for Disease Control and Prevention (CDC) has said that in light of what is known about the omicron, they are changing the self-isolation period to five days.
Now the British health minister has announced that the self-isolation period of people with a positive corona test will be shortened to five days in England and they will be able to leave the isolation after two negative transverse flow tests (done 24 hours apart) from the fifth day, regardless of their vaccination status. As a medical microbiologist, I am concerned that there is little scientific evidence to justify the safety of these reduced measures. Editor’s note: A similar decision was made today by the Ministry of Health in Israel.
Some argue that the omicron is “moderate” and does not cause a sharp increase in hospitalizations, but keep in mind that this wave is spreading in a population with a high degree of protection resulting from a combination of natural infection and immunity derived from vaccines. The biggest impact, certainly in the UK, seems to be the absences that make it difficult for essential services to function. So are economic factors outweighing scientific justifications in corona management programs?
We will examine the scientific reasons for the recommended isolation periods. A comprehensive systematic review in the UK of 79 articles from around the world surveyed virus transmission in 5,340 infected people. Assess not only the viral load determined by PCR testing, which may remain positive for some time after clinical recovery, but also whether these individuals are contagious. The review showed low viral load in the first two days, but then peaked around the third to sixth day, and then decreased on the seventh to ninth day to the inability to infect on the tenth day. That is, the data support ten-day isolation.
In an unpublished Japanese study we examined the virus shedding attributed to Omicron, and even there they found that the most virus shedding is on the third to sixth day after the onset of symptoms. In addition, a small study from the University of Exeter found that one in three people is still potentially contagious after five days.
Scientific evidence suggests that on Thursday people will still shed viable viruses, which could potentially cause significant spread of the corona. So what is the scientific evidence that the government relies on to shorten isolation periods?
Social and economic pressures
Lateral flow tests are a quick and practical way to measure adhesiveness, but they are done at home and not always according to strict criteria, meaning the results can be incorrect. Taking the swab sample is critical in performing the test, and the tester should report the test results correctly. Social and economic pressures can entice the examiner to compromise testing and reporting practices.
When the isolation period is shortened to five days, there is a risk of returning infected people to the community when they are at the peak of the spread of infectious viruses. It is hurried and dangerous towards those around them. People want to feel safe when they are outside, and know that other people are properly tested and isolated until they no longer endanger others.
I urge policymakers to examine the scientific data and draw logical, informed and correct conclusions.
More on the subject on the Yadan website: