Why Some People Get COVID While Others Don't

A London professor claims recent studies indicate that the likelihood of becoming infected with COVID-19 from a member of a household are "not as high as you'd imagine."

Danny Altmann, professor of immunology at Imperial College London, told CNBC that the focus of research is now shifting to why some individuals never seem to get COVID despite being in close contact with others who have tested positive.

Last month, Imperial College London published new research claiming individuals with higher levels of T cells (found in the immune system) from common cold coronavirus were less likely to become infected with SARS-CoV-2, a virus that causes COVID-19 and "being exposed to the SARS-CoV-2 virus doesn’t always result in infection, and we’ve been keen to understand why,” Dr. Rhia Kundu, first author of the study fro Imperial's National Heart and Lung Institute, wrote via CNBC.

“We found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect against Covid-19 infection,” Kundu wrote.

Kundu, however, cautioned that the discovery was "only one form of protection" and individuals shouldn't rely "on this alone," but rather that being fully vaccinated was "the best way to protect yourself against COVID-19," which includes "getting your booster dose."

Last month, a study published on Nature.com reported researchers assessed 52 COVID-19 household contacts in order to observe the individuals' immune responses at the earliest timepoints following exposure to SARS-CoV-2 to determine why individuals in close contact didn't get infected with the coronavirus.

The study found that individuals who were previously exposed to other coronaviruses were able to make memory immune 'T cells' which provided protection against SARS-CoV-2.

Researchers found that the memory T cells created were responsible for some household contacts testing negative despite being in close proximity to someone who had tested positive.

Additionally, despite varying coronaviruses causing different illnesses and behaving in different ways, they still share similar characteristics within the COVID family and structural similarities allow immune cells to recognize the COVID types from each other.