As you get older, your immune system does decline, but in general, people have different immune systems. Research studies have looked to unravel this by following the immune health of identical twins over time. What has been found is that genetics is not only the primary modulator of immune function and an important factor is also our environment. We are constantly exposed to viruses, and this exposure can change our immune system’s response and the way the body creates antibodies. When exposed to a virus, whether we develop symptoms and get sick is determined by how our body’s immune system responds. For example, if you get the flu, you may not always get sick.
The SARS-CoV-2 virus is part of the family of coronaviruses called the beta coronaviruses. SARS-Cov-1 was responsible for the original SARS outbreak in 2002, the MERS-1 in the Middle East and two different ones are responsible for the common cold. Coronaviruses are only responsible for between 15% and 20% of the common cold cases.
Interestingly, studies show that these two beta coronaviruses responsible for some of the common cold cross-react with the SARS-CoV-1, of which the sequence is very homologous to the SARS-CoV2 virus. In the USA, the centres for disease control and prevention (CDC) has conducted studies on SARS-CoV-2, where they found that people infected with SARS-CoV-2 also boost their antibodies against the common cold.1 So, could one or two of these common virus antibodies interact with the SARS-CoV-2 virus and neutralize it? We don’t have any answers yet, but it’s an interesting hypothesis.