New Delhi, Dec 17 (IANS): While the rapid spread of Covid-19 can be attributed mainly to the high transmissibility of the SARS-CoV-2 virus, a new study has linked the high incidence and mortality rates with environmental factors, particularly with PM2.5.

Researchers from the National Yang Ming Chiao Tung University in Taiwan proposed the theory that PM2.5 influenced the transmission of SARS-CoV-2 and the subsequent severity of the disease.

Many previous studies have demonstrated a correlation between the morbidity of Covid-19 and air pollution levels. The studies hinted that PM2.5 may act as an environmental carrier facilitating the transmission of SARS-CoV-2.

The novel research, published in the Journal of Hazardous Materials, in mice, found that PM2.5 instillation induced the protein abundance of ACE2 -- the receptor for SARS-CoV-2 -- and then increased SARS-CoV-2 pseudovirus infection in vitro and in vivo.

“Our current results provide the first in vitro and in vivo evidence that PM2.5 exposure increased ACE2 expression and deteriorated SARS-CoV-2 infection. PM2.5 instillation dysregulated the expression of RAS proteins, increased the protein abundance of ACE and ACE2 in the lungs of mice, and upregulated the morbidity of SARS-CoV-2,” the team said in the paper.

Another recent study, published in Environmental Health Perspectives, linked air pollution with longer duration of long Covid symptoms like fatigue, breathlessness, and cognitive issues.

Researchers from the Barcelona Institute for Global Health (ISGlobal) in Spain showed that air pollution can impact the severity of acute infection. As a result, exposure to PM2a.5 and PM10 can raise the risk of persistent long-Covid symptoms.

While air pollution was not directly responsible for long-Covid, it could increase the severity of the initial infection, which, in turn, raises the risk of long Covid, the researchers noted.