Within the early morning of August 16, a 41-year-old man in China’s southwest-central municipality of Chongqing bought up and went for a jog alongside a lake in an area outside park—one thing that ought to have been a nice, if not unremarkable, outing. However what actually occurred throughout that 35-minute jaunt has now sparked worldwide alarm and debate, with some scientists uncertain of China’s startling account.
In keeping with the Chinese language Heart for Illness Management and Prevention, the unmasked man contaminated 33 unmasked park guests and two unmasked park employees with the coronavirus omicron subvariant BA.2.76 throughout his quick run. The company claimed transmission occurred in fleeting outside encounters as he trotted previous individuals on a four-meter-wide foot path. Many others have been contaminated with none shut encounter. Twenty of the 33 contaminated park goers grew to become contaminated by merely visiting outside areas of the park the jogger had beforehand handed by, together with an entrance gate. The 2 contaminated employees, in the meantime, rapidly handed the an infection on to 4 different colleagues, bringing the jogger’s park outbreak whole to 39.
To help these uncommon conclusions, the CCDC cited case interviews, park surveillance footage, and SARS-CoV-2 genetic knowledge, which reportedly linked the circumstances however is notably absent from the report.
The report’s claims, if correct, would recommend a big replace is to ensure that our present understanding of SARS-CoV-2 transmission dangers. Although transmission outdoor is thought to be attainable, it is thought of far much less possible than transmission indoors, the place virus particles can grasp in stagnant air and construct up in enclosed areas over time. Out of doors encounters which are transient are particularly not thought of a big threat, as huge volumes of transferring air rapidly disperse infectious doses of viral particles. For a similar motive, SARS-CoV-2 shouldn’t be thought to linger in menacing clouds outdoor in an contaminated particular person’s wake.
For now, specialists outdoors China usually are not revising their considering on transmission dangers, citing the report’s lacking genetic knowledge and different questionable conclusions.
Given China’s strict “zero COVID” technique, the CCDC dismissed outright the likelihood that infections have been a part of an undetected outbreak within the higher neighborhood, calling publicity to the jogger (aka “affected person zero”) the “solely attainable publicity.”
The CCDC claims that genetic knowledge hyperlinks all of the circumstances collectively, exhibiting that affected person zero was the supply of the 39 infections. Particularly, they report that 29 of the 39 circumstances had “the very same gene sequencing as Affected person Zero; 5 circumstances had a mutation web site added to Affected person Zero’s gene sequence; and the opposite 5 circumstances couldn’t be sequenced due to unqualified specimens.” However there isn’t a sequencing knowledge included with the report, and it is unclear what sequencing was really accomplished to help their claims.
“If that they had sequence knowledge that confirmed 29 circumstances had equivalent genomes to ‘affected person zero,’ that might recommend that every one the circumstances got here from a single supply,” virologist Angela Rasmussen informed Ars. Rasmussen is a researcher on the Vaccine and Infectious Illness Group on the College of Saskatchewan and an affiliate at Georgetown College Heart for World Well being Science and Safety.
“However,” she mentioned, “it’s unclear whether or not they did entire genome sequencing of all of the circumstances, what sequencing platform they used (Illumina vs Nanopore) and so forth.” The report solely mentions “gene sequencing,” which can recommend solely partial genome sequencing, not “entire genome sequencing” that might positively point out a direct hyperlink between the circumstances. With out understanding the sequencing knowledge and strategies, it is not possible to substantiate if the jogger was the supply.
The CCDC additionally presents a puzzling clarification of how the jogging affected person zero got here to be contaminated within the first place.
Affected person zero
In keeping with the CCDC, the person grew to become contaminated from a obscure “publicity to contaminated airline environments.” The person had taken a visit from Chongqing to the northern metropolis of Hohhot on August 11, and flew again to Chongqing on August 13—three days earlier than his jog. Neither flight had any recognized SARS-CoV-2 circumstances on board that might clarify the person’s an infection. However, the airplane he took for the returning journey had transported 4 SARS-CoV-2-positive passengers the day earlier than, on August 12.
On August 12, 4 passengers from Tibet took the airplane from Chongqing to Hohhot and later examined optimistic in Hohhot. The airplane, in the meantime, wasn’t disinfected after their flight, and the Chongqing man boarded the subsequent day and sat (in seat 33K) close to the place three of the contaminated passengers had been sitting (seats 34A, 34C, 34H). It is unclear how the person may have develop into contaminated this fashion—SARS-CoV-2 shouldn’t be recognized to linger within the air for such lengthy intervals, and transmission from contaminated surfaces is uncommon. Furthermore, the report doesn’t point out that another passengers on the flight additionally grew to become contaminated, together with individuals who really sat in the identical seats because the passengers from Tibet. However affected person zero was contaminated with BA.2.76, which was circulating in Tibet, which led the CCDC to conclude a connection.
“I believe it’s additionally very doubtful that ‘affected person zero’ was contaminated on that airplane,” Rasmussen mentioned. “I observed that the prior flight with the passengers that have been supposedly the supply of the an infection got here from Chongqing—that might recommend cryptic unfold of BA.2.76 in Chongqing, not (simply) Tibet because the paper claims. On this case, if a complete bunch of individuals in Chongqing have BA.2.76, the sequencing knowledge may simply level to a a lot bigger outbreak in Chongqing, however you’d want the precise sequencing knowledge to essentially work out what’s occurring.
“Backside line: any claims about what the info really reveals relies on really together with the info within the paper,” she mentioned. “In any other case it’s simply hypothesis.”