A fishing vessel that left Seattle in May returned with an unexpected catch: the first direct evidence in humans that antibodies to coronavirus infection can be prevented.
More than one hundred crew members aboard the American Dynasty were hit at sea over 18 days by the infection. But only three sailors who initially carried antibodies remained virus-free, according to a new report.
Although the study is small, it addresses one of the most important questions in the pandemic: whether the immune response to one bolt with the virus protects against reinfection.
“Knowing the answer to this question is critical to vaccine design and epidemiology,” tweeted Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle and one of the study’s authors.
The study was posted online last week and has not yet been published in a peer-reviewed journal. However, the findings sparked optimistic conversations among scientists, who have relied on monkey studies for evidence of the potency of antibodies.
“I thought it was very exciting – good enough news that I told my family about it,” said Michal Tal, an immunologist at Stanford University who was not involved in the work.
Several research teams have reported that an encounter with the virus triggers a robust immune response in most people, including those who may have been mildly ill. And the vaccine candidates now in trials also appear to be producing strong neutralizing antibodies, the kind that can block the virus.
But the amount of those antibodies needed to prevent the virus from returning is unclear. Scientists measure neutralizing antibodies in titers, an indication of their concentration in the blood.
The three sailors who remained protected against the virus had widely varying titers; two had only moderate amounts, a finding that the researchers said was reassuring.
“People have been so worried about the titers and the titers going down,” said Drs. Alexander Greninger, a virologist at the University of Washington in Seattle.
The results indicate that even moderate titers prevent reinfection in a situation where the exposure to the virus was high, he said: ‘These are achievable titers, right? Hopefully it will be useful to see, and makes me very optimistic about the faxes. “
The American dynasty carried 113 men and nine women. All crew members were tested for both viruses and antibodies as part of a routine screening before sailing. (The researchers did not have access to the results of two members.)
The trawler returned to shore after 18 days at sea when a crew member became ill enough to require hospitalization. The sailors were re-tested for the presence of virus and antibodies and up to 50 days after their return.
The three sailors confirmed that they had neutralizing antibodies during the study did not test positive for the virus; 103 of the remaining 117 were infected.
These numbers may be small, but they are very important, said Dr. Branches.
“A lot of people, when they see this, are ‘Oh come on, it could be by random chance,'” he said. In fact, the chance that the results are just chance is very low, he added.
The coronavirus breaks out>
Frequently Asked Questions
Updated August 17, 2020
-
Why does standing six feet apart help others?
- The coronavirus spreads primarily by drips from your mouth and nose, especially when you cough or sneeze. The CDC, one of the organizations using this measure, bases its six-foot recommendation on the idea that most large droplets that expel people when they cough or sneeze fall within six feet to the ground. But six feet has never been a magic number that guarantees complete protection. Noses, for example, can launch drops much farther than six feet, according to a recent study. It’s a rule of thumb: you need to be the safest to stand six feet apart, especially when it’s windy. But always wear a mask, even if you think you are far enough apart.
-
I have antibodies. Am I immune now?
- At the moment, that probably seems like at least several months. There have been horrific accounts of people suffering from what appears to be a second bolt of Covid-19. But experts say these patients may have a prolonged course of infection, with the virus taking a slow toll weeks to months after initial exposure. People infected with the coronavirus typically produce immune molecules called antibodies, which are protective proteins made in response to an infection. These antibodies may only last two to three months in the body, which may seem worrying, but that is perfectly normal after an acute infection progresses, said Dr. Michael Mina, an immunologist at Harvard University. It could possibly get the coronavirus back up, but it is highly unlikely that it would be possible in a short window of time from initial infection or the second time safe.
-
I am a small business owner. Can I get relief?
- The incentive bills introduced in March provide assistance to the millions of American small businesses. Those eligible for support are non-profit companies and organizations with less than 500 workers, including sole proprietorships, independent contractors and freelancers. Some larger companies in some sectors are also eligible. The assistance provided, which is managed by the Small Business Administration, includes the Paycheck Protection Program and the Economic Damage Disaster Program. But many people have not seen payments yet. Even those who have received help are confused: the rules are draconian, and some are stuck on money they do not know how to use. Many small business owners get less than they expected or heard nothing at all.
-
What are my rights if I am worried about returning to work?
-
What will school look like in September?
- It is unlikely that many schools will return to a regular schedule this fall, requiring the grinding of online learning, easy childcare and stunted workdays to continue. The two largest public school districts of California – Los Angeles and San Diego – said on July 13 that instruction will be remote only in the fall, citing concerns that growing coronavirus infections in their areas pose too great a risk to students and teachers. Together, the two districts enroll about 825,000 students. They are the largest in the country to date to abandon plans for even a partial physical return to classes when they reopen in August. For other districts, the solution will not be an all-or-nothing approach. Many systems, including the nation’s largest, New York City, are creating hybrid plans that include some days attending classrooms and other days online. There is no national policy yet, so check regularly with your municipal school system to see what is happening in your municipality.
Other experts agreed. “Just looking at the numbers, it becomes clear that it is unlikely that all three of these people were protected by chance,” said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York.
Dr. Krammer and his colleagues monitor antibody levels in people who have once recovered from the coronavirus to see at what point they may be vulnerable to reinfection. The team started with people in New York, but the virus is circulating at such low levels in the city now that Dr. Krammer and his colleagues had to expand the study to other locations.
Data from vaccine studies will also identify the antibody titers needed to switch off the virus. But in the meantime, “this is the first evidence in humans,” said Dr. Krammer. “It made my weekend.”
The study raised other questions. Based on Abbott Architect’s test, six of the 120 people who were tested for the boat’s departure had antibodies to the virus, indicating earlier exposure.
But when the researchers reanalyzed those samples using more refined tests, only three of the six were confirmed to have antibodies, suggesting that three test results were false positives.
The Abbott test is advertised as having less than one false positive return for every 100 samples. “That’s a bit about the fact that the Abbott may be a little less specific than we thought,” Drs. Tal.
The researchers also saw antibodies in the blood, as most teams do. But those levels may not be the same as those in the nose or in saliva, the two main entry points for infection, added Drs. Tal.
“We’re looking in the wrong place,” she said. “If we want to look at protection against reinfection, we have to look in the nose.”
