OTHER strains of human coronaviruses, such as those that cause the common cold, circulated through the human population before the emergence of SARS-CoV-2, which is responsible for COVID-19.
Understanding the immune response to coronaviruses that existed before the pandemic and the current SARS-CoV-2 virus may be a gateway to better understanding protective immunity to COVID-19.
A recent study asks whether exposure to pre-pandemic coronaviruses might protect against COVID-19.
Scientists at the University of Zurich (UZH) in Switzerland recently performed an analysis demonstrating a higher level of immunity against COVID-19 in people who had been exposed to coronaviruses circulating before the pandemic.
Prof. Alexandra Trkola, lead researcher and head of the Institute of Medical Virology at UZH, and her colleagues reported their findings in Nature CommunicationsTrusted Source.
The study monitored antibody response to SARS-CoV-2 to uncover correlations with vaccine protection, disease severity, and susceptibility to infection.
The researchers also compared immune responses against SARS-CoV-2 with those against pre-pandemic coronaviruses, known as HCoVs.
The four typesTrusted Source of HCoVs that cause the common cold collectively account for around 10–15% of adult infections and 2–6% of all hospital admissions for lower respiratory tract infections.
“Our study shows that a strong antibody response to human coronaviruses increases the level of antibodies against SARS-CoV-2.
So someone who has gained immunity to harmless coronaviruses is therefore also better protected against severe SARS-CoV-2 infections,” says Prof. Trkola.
When an immune response against one coronavirus creates immune protection against a different virus, health experts call it cross-reactivity.
The researchers analyzed serum samples from 825 participants taken before the pandemic, and assessed their immune responses to four of these HCoVs. They also analyzed 389 serum samples from individuals who tested positive for SARS-CoV-2.