Why you can lose sight of the new variants that emerge from the coronavirus

This week, the Director-General of the World Health Organization, Tedros Adhanom Ghebreyesus, expressed concern that “several countries are drastically reducing diagnostic tests” for COVID-19.

“This inhibits our ability to see where the virus is, how it is spreading and evolving. Testing remains a vital tool in our fight against the pandemic, as part of a comprehensive strategy,” said the official who observes that there is a real risk that scientists around the world will “lose sight” of new variants of the coronavirus as tests plummet and dismantles the key surveillance infrastructure for this pathogen that has not yet left.

Questions about how long or how often SARS-CoV-2 could follow its replication had already been raised with the emergence of the BA.2 subvariant, which, although it generated mild cases of the disease, its transmission rate caused outbreaks almost worldwide. This week, the UN health agency said it is tracking the emergence of two new subvariants of the highly contagious Ómicron variant, known as BA.4 and BA.5, which have slightly different characteristics than the “original” strain BA.1 and its sister variant BA.2. Scientists in South Africa and Botswana have detected 27 cases, while BA.4 has also been confirmed in the United Kingdom, Belgium, Denmark and Germany.

Dr. Maria Van Kerkhove, WHO's chief technical officer for COVID-19, said Wednesday that while there are “very few sequences” available so far, both BA.4 and BA.5 were added to the agency's monitoring list as scientists rush to understand the impact of additional mutations. Viruses are constantly changing as they replicate, but occasionally a mutation arises that affects their ability to spread, evade previous immunity, or affect the severity of the disease they cause. For example, BA.2, which now accounts for about 94 percent of all sequenced cases, is more contagious than other variants of Omicron.

“What we're seeing right now [with BA.4 and BA.5] is... transmissibility, is there any change in gravity? Is there any change in our ability to defend ourselves against this, including diagnoses, vaccines, therapies?” , Van Kerkhove wondered. And he immediately said: “There is no sign that the variants are changing the epidemiological situation, but with only eight complete sequences of the genome it is too early to know for sure. This is why it is so important that we continue to monitor and track this virus as it changes.”

But Dr. Mike Ryan, head of WHO's emergency program, said there is a risk that Sars-Cov-2, the virus that causes COVID, “goes underground” as testing and sequencing rates fall around the world. Both Denmark and the United Kingdom, which have been leaders in genome sequencing during the pandemic, have recently announced that they will reduce costly programs as part of efforts to “live with the virus”. “We in the scientific and public health community must continue to track this virus closely, at every moment. However, in the rush to leave the pandemic behind us, we are in danger of losing some of the valuable infrastructure, human workforce and technological infrastructure, which we have developed over the past two years,” he said.

On Tuesday and Wednesday, WHO launched a public consultation on what a 'pandemic treaty' should look like based on the current International Health Regulations, a process described as a once-in-a-generation opportunity by Adhanom Ghebreyesus. Maintaining early warning and global surveillance systems will be critical to any effort to prevent outbreaks from turning into pandemics, Ryan recalled. “We need to focus on the future, this pandemic was a warning shot for our civilization. This was very terrible, the next one could be worse. I hope it never happens, but I don't want the world to be in the same situation as it was at the beginning of this pandemic at the beginning of the next one,” said the official.

The phenomenon of home testing

The official count of coronavirus infections in the United States has always been an understatement. But as Americans increasingly turn to home testing, states close mass testing sites and institutions reduce surveillance testing, case counts are becoming an increasingly unreliable measure of the actual number of victims of the virus, scientists say.

A growing reliance on home testing and the closure of mass testing sites are making official case counts less reliable, they add. “It seems that blind spots are getting worse over time,” said Denis Nash, an epidemiologist at CUNY's Graduate School of Public Health and Health Policy who led the analysis of New York City, which is preliminary and yet to be published.

In New York City, for example, officials recorded more than 538,000 new cases between January and mid-March, representing approximately 6 percent of the city's population. But a recent survey of New York adults suggests that there could be more than 1.3 million additional cases that were never detected or never reported, and that 27 percent of the city's adults may have been infected during those months.

“That could leave officials increasingly in the dark about the spread of the new highly contagious subvariant of Ómicron known as BA.2 ″. On Wednesday, New York officials announced that two new subvariants of Ómicron, both descendants of BA.2, have been circulating in the state for weeks and are spreading even faster than the original version of BA.2.

To track BA.2, as well as future variants, staff members should obtain as much information as they can from a range of existing indicators, including hospitalization rates and wastewater data. But really controlling the virus will require more creative thinking and investment, scientists said. For now, people can measure their risk by implementing a low-tech tool: pay attention to whether people they know are contracting the virus.

The general tiredness caused by the coronavirus, as well as the protection provided by vaccination against severe symptoms, can also cause fewer people to undergo tests, experts say. And citing the lack of funding, the federal government recently announced that it would stop reimbursing healthcare providers for the cost of testing uninsured patients, prompting some providers to stop offering those tests for free. That could make uninsured Americans especially reluctant to get tested.

Tracking case trends remains important. “If we see an increase in cases, it is an indicator that something is changing, and quite possibly that something is changing due to a greater impact on the system, such as a new variant,” concluded Alyssa Bilinski, public health policy expert at Brown University's School of Public Health.

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