Reports: COVID-19 immunity can last for months

Cloth face coverings slow coronavirus spread, evidence shows

One study found that antibodies that protect against infection can last for at least five months

Three new reports support the idea of long-lasting immunity to COVID-19.

CNN reported Wednesday that several recently published studies indicate many people who recover from coronavirus infections are protected for at least some length of time. They’re also indicative of how vaccines for the coronavirus could shield people from infection for longer than a few weeks.

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In a study led by Deepta Bhattacharya, an immunobiologist at the University of Arizona College of Medicine, people were found to create antibodies that protect against infection and last for at least five to seven months. The findings were published Tuesday in the journal Immunity.

“We have one person that is seven months out. We have a handful of people that are five to seven months out,” Bhattacharya told CNN.

Since April 30 after they developed a coronavirus blood test, Bhattacharya’s team has been collaborating with county officials to test volunteers in Arizona. Nearly 30,000 people have been tested and the team has evaluated some who have been tested multiple times.

Knowing precisely how long COVID-19 immunity will last, however, will take some time since the novel coronavirus has only been around for under a year.

“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,” Bhattacharya said.

In the other two studies, each of which was published last week, subjects with COVID-19 had elevated levels of antibodies, especially in severe cases. They also supported the thought that immunity could be long-lasting.

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More than 300 coronavirus patients were tested by Massachusetts General Hospital researchers. Most of the patients were severely ill and hospitalized. For as long as months, their levels of IgG antibodies were elevated. The findings were published in the American Association for the Advancement of Science journal, Science Immunology.

“Knowing how long antibody responses last is essential before we can use antibody testing to track the spread of COVID-19 and identify ‘hot spots’ of the disease,” said pediatric infectious disease specialist Dr. Jason Harris, who worked on the study.

In a Canadian team’s study, also published in Science Immunology, patients' IgG antibodies lasted for as long as 115 days after their symptoms initially developed. Researchers used saliva tests in their study.

“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],” researchers said in the abstract. “IgG responses in saliva may serve as a surrogate measure of systemic immunity to SARS-CoV-2 based on their correlation with serum IgG responses.”

It’s important to note that despite talk of herd immunity, these reports don’t support the notion that any country could get there soon via natural infection.

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