Animal origin seen as likely virus start
WHO-China team throws doubt on theory of lab leak in pandemic
WUHAN, China — The coronavirus most likely first appeared in humans after jumping from an animal, a team of international and Chinese scientists looking for the origins of the virus said Tuesday, saying an alternative theory that it leaked from a Chinese lab was unlikely.
A closely watched visit by World Health Organization
experts to Wuhan — the Chinese city where the first coronavirus cases were discovered — did not dramatically change the current understanding of the early days of the pandemic, said Peter Ben Embarek, the leader of the WHO mission.
But it did “add details to
that story,” he said at a news conference as the group wrapped up a four-week visit to the city.
And it allowed the joint Chinese-WHO team to further explore the lab leak theory and decide it was unlikely. The Wuhan Institute of Virology is home to many different virus samples, leading to allegations that it may have been the source of the original outbreak, whether on purpose or accidentally.
Embarek, a WHO food-safety and animal-disease expert, said experts now consider the possibility of such a leak so improbable that it will not be suggested as an avenue of future study. But another team member, Danish scientist Thea Koelsen Fischer, told reporters that team members could not rule out the possibility of further investigation and new leads.
China had already strongly rejected the possibility of a leak and has promoted other theories. The Chinese and foreign experts considered several ideas for how the disease first ended up in humans, leading to a pandemic that now has killed more than 2.3 million people worldwide.
In recent days, Chinese state media outlets have preempted Tuesday’s news conference with reports declaring Wuhan has been “cleared of guilt” as the suspected origin of the pandemic, with some echoing the Chinese Foreign Ministry in calling for an investigation into U.S. labs.
Embarek said the initial findings suggest the most likely pathway the virus followed was from a bat to another animal and then to humans, adding that would require further research.
“The findings suggest that the laboratory incidents hypothesis is extremely unlikely to explain the introduction of the virus to the human population,” he said.
Asked why, Embarek said accidental releases are extremely rare and that the team’s review of the Wuhan institute’s lab operations indicated it would be hard for anything to escape from it.
He also noted that there were no reports of this virus in any lab anywhere before the pandemic. Liang Wannian, the head of the Chinese side, also emphasized that, saying there was no sample of it in the Wuhan institute.
But that line of reasoning that drew skepticism from outside experts.
“If the only information you’re allowing to be weighed is provided by the very people who have everything to lose by revealing such evidence, that just doesn’t come close to passing the sniff test,” said David Relman, a microbiologist at Stanford University.
Relman suggested that the WHO team should have sought complete, detailed records from the laboratories about their experiments and the raw genomic sequence data of their research going back a decade.
Raina MacIntyre, professor of biosecurity at the University of New South Wales in Australia, was also surprised to see the idea of a lab accident ruled out so quickly.
Without exploring all leads, she suggested, “We may never know the origins of this virus.”
ACCESS PRAISED
The mission was intended to be an initial step in the process of understanding the origins of the virus, which scientists have posited may have passed to humans through a wild animal, such as a pangolin or bamboo rat. Transmission directly from bats to humans or through the trade in frozen food products are also possibilities, Embarek said.
The WHO team’s visit is politically sensitive for Beijing, which is concerned about being blamed for alleged missteps in its early response to the outbreak. An Associated Press investigation has found that the Chinese government put limits on research into the outbreak and ordered scientists not to speak to reporters.
Still, one member of the WHO team, British-born zoologist Peter Daszak, said last week that they enjoyed a greater level of openness than they had anticipated, and that they were granted full access to all sites and personnel they requested.
Koelsen Fischer said she did not get to see the raw data and had to rely on an analysis of the data that was presented to her. But she said that would be true in most countries.
The team — which includes experts from 10 countries who arrived Jan. 14 — visited the Huanan Seafood Market, the site of an early cluster of cases in late 2019.
Marion Koopmans, a Dutch virologist on the team, said that some animals at the market were susceptible or suspected to be susceptible to the virus, including rabbits and bamboo rats. And some could be traced to farms or traders in regions that are home to the bats that carry the closest related virus to the one that causes covid-19.
She said the next step would be to look more closely at farms.
Liang, the head of the Chinese team, said the virus also appeared to have been spreading in parts of the city other than the market, so it remains possible that the virus originated elsewhere.
The team found no evidence that the disease was spreading widely any earlier than the initial outbreak in the second half of December 2019.
“We haven’t been able to fully do the research, but there is no indication there were clusters before what we saw happen in the later part of December in Wuhan,” Liang said.
VACCINATION JUGGLING
Meanwhile, the U.S. has entered a tricky phase of the covid-19 vaccination effort as providers try to ramp up the number of people getting first shots while also ensuring a growing number of others get second doses just when millions more Americans are becoming eligible to receive vaccines.
The need to give each person two doses a few weeks apart vastly complicates the country’s biggest-ever vaccination campaign. And persistent uncertainty about future vaccine supplies fuels worries that some people will not be able to get their second shots in time.
In some cases, local health departments and providers have said they must temporarily curb or even cancel appointments for first doses to ensure there are enough second doses for people who need them.
For about the past month, the U.S. has administered an average of 900,000 first doses each day, according to data from the Centers for Disease Control and Prevention. Now many of those people are due for second doses, and states are trying to administer first doses to an expanded pool of recipients.
“It’s really important and critical to recognize that there are still not enough doses to go around,” said Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention.
So far, about 10% of the U.S. population has received at least one dose of the vaccine, About 3% has received both doses, an Associated Press analysis showed.
Across Los Angeles County, health officials say limited supplies mean the majority of vaccinations this week will be for second doses. In the state’s Napa County, some appointments for first doses were canceled last week to ensure there would be enough for second doses.
“We’re getting a lot of the questions from community members asking, ‘Is my second dose in jeopardy?’ And right now, we don’t have an answer because it’s all dependent on the inventory that comes in from the state,” said Alfredo Pedroza, a county supervisor.
Both covid-19 vaccines being distributed in the U.S. require two shots a few weeks apart to maximize protection. For Pfizer, the doses are supposed to be three weeks apart. For Moderna, it’s four weeks. But if needed, the booster can be delayed for up to six weeks, according to the CDC, which updated its guidance late last month.
State and local health officials now emphasize that extended time frame in public messaging to alleviate worries that people might not get their second shots on time. Federal officials have also said they are confident there will be enough doses to ensure people get their second shots.
SCHEDULING COMPLICATIONS
Fueling the concerns in some places is the difficulty of booking the second dose. Although many places schedule the booster when the first shot is given, others ask people to schedule them later because of logistical issues.
In Mississippi, health officials acknowledged that the process for scheduling a second shot could be challenging.
It was much like trying to schedule the first, with people having to fill in all the demographic information again, said Jim Craig of the Mississippi health department.
Now the health department says people will get an email with instructions for scheduling their second dose.
In New Hampshire, officials are ditching the current scheduling system after thousands of people struggled to book their boosters within the recommended time — with some being given appointments for two months later. People will now get appointments for their second shots when they get their first.
New Hampshire is one of several local jurisdictions that had signed up to use the CDC’s Vaccine Administration Management System.
At the Las Vegas Convention Center in Nevada, another type of scheduling problem popped up last week when the site opened as a clinic dedicated only to second doses. When appointments were made available online, people eager for their first doses snapped up slots.
“We had enough vaccine — we just need to control the crowd somehow,” said JoAnn Rupiper of the Southern Nevada Health District.
People who scheduled a first dose at the site had their appointments canceled, Rupiper said. To ensure eligible people who had trouble scoring appointments online get their second shots, the convention center is allowing walk-ins.
Despite the scheduling confusion, health officials and providers say their main challenge remains the limited supplies and the variability in how many doses are distributed from week to week. Even with the increase in shipments announced by President Joe Biden’s administration, local officials and providers say they do not have enough doses to meet demand.
The shortage is one reason why Dr. Anthony Fauci, the country’s top infectious disease expert, has noted the potential value of the one-shot vaccine by Johnson & Johnson, which recently filed for emergency use authorization. That shot is also less expensive to produce and easier to ship.
Pedroza said the cancellations last week in California’s Napa County happened after a spike in shipments a few weeks ago led the county to think it would continue getting at least as many doses. But the spike turned out to be a one-time windfall, Pedroza said.
In Seattle, University of Washington Medicine temporarily stopped taking new appointments in late January because of limited supplies, combined with the need to give others their second doses.
“If there was more supply, we would be happy to be doing more first-dose appointments,” said Cynthia Dold, associate vice president of clinical operations at University of Washington Medicine.