The requirement for Covid-19 testing for passengers traveling from China highlights growing concerns about the potential for new strains of the virus to go undetected due to the country’s growing outbreak.
While the US imposed requirements for travelers from China to show negative test results, it also developed a program that collects voluntary samples from international passengers at airports to help monitor variants entering the country. On Saturday, Canada said travelers from China, Hong Kong and Macau must produce a negative covid test, while Morocco has banned visitors from China instead.
The latest restrictions came after Britain and France on Friday joined countries trying to test passengers and sequence samples from people arriving from China in an effort to identify dangerous new mutations that could spread rapidly through the population.
The scenario echoes the early days of the pandemic, when China was criticized for not releasing key genetic data on the virus until weeks after news of the new disease became public. State health officials said sentinel hospitals monitor for mutations in samples taken from patients in emergency rooms and outpatient clinics. However, most of these data have not been shared internationally, health experts say.
“In the absence of full information from #China, it is clear that countries around the world are acting in ways they believe can protect their populations,” World Health Organization Director-General Tedros Adhanom Ghebreyesus said on Twitter. The global health group needs more detailed information from China to conduct a comprehensive risk assessment, he said.
Representatives from China’s National Health Commission and the National Disease Control and Prevention Administration briefed WHO officials on Friday on strategies and actions to combat the outbreak.
“Whoever calls for the sharing of specific and real-time data on epidemiological situations – including more genetic sequencing data, data on the impact of disease including hospitalizations, ICU admissions and deaths,” the organization said in a statement. WHO officials stressed “the importance of timely monitoring and publication of data to help China and the global community make accurate risk assessments and provide effective responses.”
Whether the Chinese outbreak has an impact on Covid trends in the US is unclear, according to Kristen Nordlund, a spokeswoman for the Centers for Disease Control and Prevention. But the agency is monitoring the situation, it said Friday in an email.
“With the lack of immunity of the Chinese population against Covid-19, there is a possibility that new variants of concern may emerge,” said Nordlund.
Business as Usual
Officials at GISAID, the consortium that tracks Covid mutations, said they were confident of the new shipments from China. The group has received nearly 1,000 genetic sequences in the past week from across the country, provided by provincial health authorities and private health care facilities.
“Variants continue to spread without change causing concern,” said Peter Bogner, founder of GISAID. “You don’t have any data to suggest anything other than business as usual.”
In other areas outside of China where the virus is spreading rapidly, sequencing efforts that could identify new variants would be lost, Bogner said. Chinese health officials said they immediately shared the sequence data with the WHO.
“There is nothing we keep to ourselves,” Wu Zunyou, chief epidemiologist at China’s Centers for Disease Control and Prevention, said Thursday. “All the work of our order has been shared with the whole world.”
Nine omicron subvariants dominate the country’s outbreak, Wu said. The limited sequence data that has been shared publicly shows that the variant is largely similar to strains found elsewhere in the world, such as BF.7 and BA.5.2, according to data analytics firm Airfinity, and there is no evidence yet that a new variant is concerned. has appeared. But it may only be a matter of time and with limited information, it is difficult to prepare for the rest of the world, experts say.
“The situation in China worries us a lot,” said Wilbur Lam, who runs the US National Institutes of Health’s RADx Tech Test Validation Core out of labs at Emory University and the Georgia Institute of Technology. The new requirement for travelers from China to show a negative test no more than two days before flying to the US is not a “perfect policy measure,” he said.
Viruses like Covid can mutate every time they reproduce. Sometimes these mutations are insignificant, or even stop the virus from growing. But in rare cases, new mutations can provide advantages that allow certain strains to spread rapidly.
Keeping up with the evolution of viruses poses a difficult challenge for drug manufacturers. For example, the updated booster image from Moderna Inc. and the Pfizer Inc. partnership. and BioNTech SE is designed to target early omicron variants B4 and B5. During the time that the shots were developed, however, these variants were replaced by the faster spreading BQ.1 and BQ.1.1 variants.
In the past few weeks, another variant called XBB has gained steam. Health experts worry that the strain is more likely to evade immune protection from vaccines and previous infections, and may lead to more elusive offspring.
‘Serious Threat’
The BQ and XBB subvariants of omicron “pose a serious threat to the current Covid-19 vaccine, making all legitimate antibodies inactive, and possibly gaining dominance in the population due to the advantage of avoiding antibodies,” researchers from Columbia University wrote in a published study. this month in the journal Cell.
A mutation in XBB, which is common in the Northeastern US, makes at least one Covid test made by DxTerity Diagnostics Inc. less reliable, US regulators said Thursday. In general, scientists have found that it takes longer for a test to be positive when there is an omicron infection, Lam said.
Despite the rapid growth of cases there, China may not yet be fertile ground for variants that evade natural or vaccine-assisted human immunity, said Sam Scarpino, director of Artificial Intelligence and Life Sciences at Northeastern University’s Institute for Experiential AI. Relatively few people there have acquired immunity provided by vaccines or previous infections so that the virus can be genetically avoided.
However, as infections continue to rise with few mitigation measures to prevent the virus from spreading in China, new variants could cause problems, Scarpino said.
“In one or two months, we want to watch closely,” he said in an interview.
–With assistance from Immanual John Milton, Dong Lyu, Michelle Fay Cortez, Fiona Rutherford and Jason Gale.