Long-Lasting Immunity Follows Serious COVID Cases
By Steven Reinberg
TUESDAY October 13, 2020 (HealthDay News) – After a severe case of COVID-19, you could have long-lasting immunity, according to a new study.
The finding is reassuring for patients because the immune system makes antibodies in response to SARS-CoV-2, the virus that causes COVID-19, the researchers said.
“But there is a great lack of knowledge about the duration of these antibody responses,” said researcher Dr. Richelle Charles of the division of infectious diseases at Massachusetts General Hospital in Boston.
His team examined more than 300 blood samples from patients with COVID-19, most of whom had severe cases. Samples were taken up to four months after symptom onset.
The researchers found that measuring an antibody called immunoglobulin G (IgG) was very accurate in identifying infected patients who had symptoms for at least 14 days. The antibody levels remained elevated for four months and were linked to elevated levels of other protective antibodies, which did not decrease over time.
“This means people are most likely protected during this time,” Charles said in a press release from the hospital. “We have shown that key antibody responses to COVID-19 persist.”
The researchers also found that patients with COVID-19 had immunoglobulin A (IgA) and immunoglobulin M (IgM) responses that dropped to low levels within 2.5 months.
“We can now say that if a patient has both IgA and IgM responses, they have probably been infected with the virus within the past two months,” Charles said.
Knowing how long an immune response lasts can help get more accurate data on the spread of SARS-CoV-2, said study co-author Dr Jason Harris, pediatric infectious disease specialist at Mass General. .
“Knowing how long antibody responses last before you can use antibody tests to track the spread of COVID-19 and identify disease ‘hot spots’ is critical,” Harris added.
The results were published online on October 8 in the journal Scientific immunology.
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