Virus antibodies fade fast but not necessarily protection

MARILYNN MARCHIONE
·3 mins read

New research suggests that antibodies the immune system makes to fight the new coronavirus may only last a few months in people with mild illness, but that doesn’t mean protection also is gone or that it won’t be possible to develop an effective vaccine.

“Infection with this coronavirus does not necessarily generate lifetime immunity,” but antibodies are only part of the story, said Dr. Buddy Creech, an infectious disease specialist at Vanderbilt University. He had no role in the work, published Tuesday in the New England Journal of Medicine.

The immune system remembers how to make fresh antibodies if needed and other parts of it also can mount an attack, he said.

Antibodies are proteins that white blood cells called B cells make to bind to the virus and help eliminate it. The earliest ones are fairly crude but as infection goes on, the immune system becomes trained to focus its attack and to make more precise antibodies.

Dr. Otto Yang and others at the University of California, Los Angeles, measured these more precise antibodies in 30 patients diagnosed with COVID-19 and four housemates presumed to have the disease. Their average age was 43 and most had mild symptoms.

Researchers found that the antibodies had a half-life of 36 days, which means that half of them would be gone after that much time. It dovetails with a previous report from China also suggesting antibodies quickly fade.

The results “call for caution regarding antibody-based ‘immunity passports,’ herd immunity, and perhaps vaccine durability,” the California authors write.

That’s true, Creech said, but other parts of the immune system also help confer protection. Besides churning out antibodies, B cells develop a memory so they know how to do that again if needed.

“They would get called into action very quickly when there’s a new exposure to the virus. It’s as if they lie dormant, just waiting,” he said.

Other white blood cells called T cells also are better able to attack the virus the next time they see it, Creech said.

Although circulating antibodies may not last long, what we need to know is if and how people remake antibodies if exposed to the coronavirus again and if they protect against another infection, Alison Criss, an immunologist at the University of Virginia, wrote in an email. “We also need to know if there is a protective T cell response” that reappears.

Vaccines, which provoke the immune system to make antibodies, might give longer-lasting protection than natural infection because they use purified versions of what stimulates that response, she noted.

Creech agreed.

“This shouldn’t dissuade us from pursuing a vaccine,” he said. “Antibodies are only a part of the story.”

___

Marilynn Marchione can be followed on Twitter at http://twitter.com/MMarchioneAP

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

___

This story was updated on July 22, 2020, to correct the half-life of coronavirus antibodies, because of an error made by the researchers. It is 36 days, not 73, according to the lead researcher.

More From

  • Trump to NYC cops: 'No one will be safe in Biden's America'

    Seeking to amplify his law-and-order message, President Donald Trump on Friday told hundreds of New York Police Department officers that “no one will be safe in Biden’s America" if the former Democratic vice president defeats him in November . Trump spoke to members of the City of New York Police Benevolent Association, the union representing some 24,000 rank-and-file officers as he steps up his attacks on Biden and his running mate, Sen. Kamala Harris. Trump was formally endorsed by the union during the event at his New Jersey golf course.

  • George Kittle signs $75M, 5-year extension with 49ers

    All-Pro tight end George Kittle has signed his five-year, $75 million extension with the San Francisco 49ers that is the richest contract ever at the position. Kittle officially signed the deal Friday, a day after agreeing to the contract that keeps him locked up in San Francisco through the 2025 season. ''I love being a 49er and am blessed to have the opportunity to wear red and gold for years to come,'' Kittle said in a statement.

  • Serena Williams loses to woman ranked 116th; Coco Gauff wins

    Entering Friday, Serena Williams had played 967 tour-level singles matches as a professional, with just four losses against opponents ranked outside the top 100 - and none in eight years. Well, it's time to add to that list: Williams was beaten by No. 116 Shelby Rogers 1-6, 6-4, 7-6 (5) in the Top Seed Open quarterfinals. Need to go even further back in the record books to find this sort of tournament exit for former No. 1 Williams: The owner of 23 Grand Slam singles titles hadn't bowed out against someone so low in the rankings since No. 111 Virginie Razzano stunned her at the 2012 French Open.

  • Heat's Derrick Jones Jr. injured in 109-92 loss to Pacers

    Doug McDermott scored 23 points and the Indiana Pacers beat Miami 109-92 on Friday in a game delayed for several minutes late in the third quarter when Heat forward Derrick Jones Jr. was carted off the court. Jones was attempting to get around a screen when he collided with 6-foot-11 Indiana center Goga Bitadze and fell to the floor. Jones lay on his stomach with his right arm on the back of his head for several minutes before he was fitted for a neck brace and carted off the floor.