New Zealand officials are scrambling to halt a growing cluster of COVID-19 cases that has baffled health investigators trying to understand how the pandemic coronavirus regained a foothold on the island nation.
Officials on Tuesday announced four cases in one family in Auckland, the largest city in New Zealand. Before that, the country had gone 102 days without any local transmission. Throughout the pandemic, New Zealand has been among the most successful countries in the world at responding to and holding back the pandemic coronavirus, relying on swift and thorough testing and tracing as well as rigorous social distancing and lockdown orders.
But the new cluster has stumped investigators, who are now exploring all the possible ways the coronavirus may have slipped back in—including that it arrived on the packaging of frozen-food shipments and infected a worker unpacking them.
Meanwhile, the cluster has grown to at least 17 as of Thursday. Auckland has been wrenched back into lockdown measures, and officials have raised the alert level for the rest of country, reinstating some restrictions.
Cold Case
The first person in the cluster to test positive was a man in his 50s who had been symptomatic for five days. Of the mans six family contacts, three also tested positive Tuesday: a preschool-aged child and two adults, according to The New Zealand Herald. One of the adults appears to be a woman in her 20s who works at the lending company Finance Now, and the other is a man who works at a facility operated by Americold, an Atlanta, Georgia-based company that transports and stores goods at controlled temperatures. Americold operates in the United States, Canada, Australia, and Argentina, as well as New Zealand.
The infected Americold employees job involved handling frozen foods destined for grocery stores and food service companies. He had been on sick leave for nine days at the time that he tested positive, according to Americold NZ Managing Director Richard Winnall, who spoke to the Herald.
Winnall stressed that the chance of the virus spreading to consumers from frozen foods the infected employee handled appeared “improbable.” He noted that the frozen-food shipments come in several layers of packaging, and the infected employee likely did not touch the packaging layers that are eventually touched by consumers or food service employees. Winnall also noted that the infected employee would have been wearing personal protective gear, including gloves, decreasing the likelihood that he transferred infectious virus onto the food packages.
“Looking at all the options”
Still, without a clear explanation of how the employee and his family were infected in the first place, health investigators are exploring the possibility that he was infected by virus particles shipped on the frozen goods. Health officials and experts suggest that this seems unlikely but not impossible. There have been several reports from China of health officials detecting genetic material of the coronavirus, SARS-CoV-2, on frozen goods. In an example this week, authorities in the eastern Chinese port city of Yantai detected traces of the virus on imported frozen seafood. The genetic traces suggest contamination with the coronavirus but not necessarily whole infectious virus particles.
New Zealands Director-General of Health Ashley Bloomfield said this week that surfaces at the Americold facility will be tested to see if frozen freight or something else may have been the source of the new infections. “We do know from studies overseas that, actually, the virus can survive in some refrigerated environments for quite some time,” he said. For the investigation, “we start by looking at all the options and ruling then out, and that's the position were in at the moment.”
Unlikely, but not impossible
The possibility that SARS-CoV-2 could survive on shipments of frozen goods isnt wild. Studies have suggested that some virus particles can remain infectious for three days on plastic surfaces at room temperature. And the virus is more stable at lower temperatures, like those in a refrigerated warehouse.
This means that the virus could remain viable for even longer, infectious disease and food safety researcher Hamada Aboubakr tells Ars. Aboubakr is a researcher at the University of Minnesota and was recently the first author of a scientific review on the stability of SARS-CoV-2 on surfaces in different conditions.
Aboubakr suggests its theoretically possible that SARS-CoV-2 could spread through contaminated food or food packaging. In addition to the cold survival, there is early laboratory data suggesting that the virus can survive highly acidic conditions, similar to the environment of the human stomach. But he notes that experts are skeptical of this. Overall, he says, “there is no sharp answer” to the risk of food and food packaging because no studies have confirmed such as link.
The point is echoed by the World Health Organization, which notes that there is “currently no evidence that people can catch COVID-19 from food or food packaging.”
Aboubakr says that investigators in New Zealand will need a lot more data and information to assess the risk of spread from freight and pin the new cases to contaminated packages.
Bad luck
Infectious-disease researcher Amandine Gamble agrees. Gamble is a researcher at the University of California, Los Angeles, who recently led a study on treatments to inactivate SARS-CoV-2. “It is very plausible that SARS-CoV-2 can remain viable on frozen surfaces for several days,” she tells Ars. “However, it is Read More – Source
[contf] [contfnew] 
arstechnica
[contfnewc] [contfnewc]
