Friday, October 16, 2020

Studies confirm Covid immunity lasts for months

New reports show coronavirus immunity can last for months | CNN - Maggie Fox:

October 14, 2020 - "Three new reports show coronavirus immunity can last for months -- and maybe even longer. The findings suggest that many, if not most, people who recover from coronavirus infections are protected for at least a period of time. They also suggest that coronavirus vaccines may be able to protect people for more than just a few weeks.

"One study found that people produce antibodies that protect against infection and last for at least five to seven months. 'We have one person that is seven months out. We have a handful of people that are five to seven months out,' Deepta Bhattacharya, an immunobiologist at the University of Arizona College of Medicine, told CNN. 'We conclude that neutralizing antibodies are stably produced for at least 5-7 months after SARS-CoV-2 infection,' his team wrote in a report published in the journal Immunity on Tuesday.

"They have been working with county officials to test volunteers in Arizona since April 30, ever since they developed a blood test for coronavirus.... The team has tested close to 30,000 people and has looked at some who have been tested several times....

"The novel coronavirus has only been around for less than a year, so it will take time to know just how long immunity lasts. 'That said, we know that people who were infected with the first SARS coronavirus, which is the most similar virus to SARS-CoV-2, are still seeing immunity 17 years after infection. If SARS-CoV-2 is anything like the first one, we expect antibodies to last at least two years, and it would be unlikely for anything much shorter,' he said. The severe acute respiratory syndrome virus infected close to 8,000 people and killed about 800 before it was stopped in 2004.

"People who were sicker with Covid-19 had a stronger immune response, Bhattacharya said. 'The people sampled from the ICU had higher levels of antibodies than people who had milder disease.' He doesn't yet know what that will mean for long-term immunity. Plus, the researchers have not checked to see if people were exposed to the virus a second time and were able to resist becoming infected again....

"However, two other studies support the idea of long-lasting immunity.

"Researchers at Massachusetts General Hospital tested 343 coronavirus patients, most of them severely ill in hospital. They had elevated levels of certain antibodies called IgG antibodies for up to four months, they reported in the journal Science Immunology last week. 'We showed that key antibody responses to Covid-19 do persist," infectious disease specialist Dr. Richelle Charles of Massachusetts General Hospital said in a statement. Two other antibody types -- IgM and IgA -- first spiked and then crashed in these patients. 'We can say now that if a patient has IgA and IgM responses, they were likely infected with the virus within the last two months,' Charles said....

"A Canadian team used saliva tests and had similar findings. Their patients had IgG antibodies that lasted up to 115 days after they first developed symptoms. 'This study confirms that serum and saliva IgG antibodies to SARS-CoV-2 are maintained in the majority of COVID-19 patients for at least 3 months post symptom onset.' they wrote in Science Immunology."

Read more: https://www.cnn.com/2020/10/14/health/lasting-immunity-covid-19-antibodies-studies/index.html

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