Immunity to previous cold may make COVID-19 worse

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A new study from the University of Rochester found prior infection and immunity to one of the common cold coronaviruses may have put people at risk of more severe COVID illness and death.

The study is published in the Journal of Infectious Diseases and was conducted by Martin Zand et al.

At the beginning of the COVID pandemic, there was hope that pre-existing immunity to the common cold could protect you from COVID, but the new evidence suggests that sometimes the opposite can happen.

In the study, the team examined immunity to various coronaviruses, including the COVID-causing SARS-CoV-2 virus, in blood samples taken from 155 COVID patients in the early months of the pandemic.

Of those patients, 112 were hospitalized and provided sequential samples over the course of their hospitalization.

The team found these hospitalized patients experienced a large, rapid increase in antibodies that targeted SARS-CoV-2 and several other coronaviruses.

While big boosts in antibodies—protective proteins generated by the immune system—is usually a good thing, in this case, it wasn’t.

The researchers found that these antibodies were targeting parts of the spike protein (which sits on the surface of coronaviruses and helps them infect cells) that were similar to common cold coronaviruses the immune system remembered from previous infections.

Unfortunately, targeting those areas meant the antibodies could not neutralize the new SARS-CoV-2 virus.

When levels of these antibodies rose faster than levels of SARS-CoV-2 neutralizing antibodies, patients had a worse disease and a higher chance of death.

The team says in people who were sicker—those who were in the ICU or died in the hospital, the immune system was responding robustly in a way that was less protective.

It took those patients longer for the immune system to make protective antibodies… unfortunately, too late for some.

This study adds to a growing pool of evidence that a phenomenon called immune imprinting is at play in COVID immune responses.

The team likens this phenomenon to “immune distraction”: immunity to one threat (seasonal coronaviruses) hijacks the immune response to a new, but similar threat (SARS-CoV-2).

Immune imprinting has been linked to poor immune responses to other viruses, like flu, and can have implications for vaccine strategies.

By some predictions, COVID is likely to be with humans for a long time—with new, milder strains emerging and circulating on an annual or seasonal basis.

If those predictions hold true, the study suggests that we will need to regularly develop new vaccines targeting the new strains of SARS-CoV-2.

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If you care about COVID, please read studies about people who are more likely to get severe COVID-19 after vaccination, and findings of vitamin D deficiency linked to severe COVID-19 and death.

For more information about COVID, please see recent studies about drug that can offer much-needed COVID-19 protection, and results showing scientists find new antibody treatment for COVID-19.

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