Although studies have identified risk factors for SIDS, such as putting infants to bed on their bellies, there has been little understanding of the syndromes biological process or its potential causes. Deaths from SIDS are unlikely to be due to a single cause, but rather to multiple risk factors. The frequency of SIDS does appear to be influenced by social, economic, or cultural factors, such as maternal education, race or ethnicity, or poverty. SIDS is believed to occur when an infant with an underlying biological vulnerability, who is at a critical development age, is exposed to an external trigger. The following risk factors generally contribute either to the underlying biological vulnerability or represent an external trigger:

Tobacco smoke
SIDS rates are higher in babies of mothers who smoke during pregnancy. Between no smoking and smoking one cigarette a day, on average, the risk doubles. About 22% of SIDS in the United States is related to maternal smoking. SIDS correlates with levels of nicotine and its derivatives in the baby. Nicotine and derivatives cause alterations in neurodevelopment. Sleeping
Placing an infant to sleep while lying on the belly or side rather than on the back increases the risk for SIDS. This increased risk is greatest at two to three months of age. Elevated or reduced room temperature also increases the risk, as does excessive bedding, clothing, soft sleep surfaces, and stuffed animals in the bed. Bumper pads may increase the risk of SIDS due to the risk of suffocation.
In April 2020, Lawrence Berkeley National Laboratory conducted a X-ray crystallography study at Virs request to investigate how such antibodies bind to SARS-CoV-2 at the molecular level. The Berkeley Lab data helped Vir identify candidates for further study, and Vir eventually settled on a single candidate antibody, S309. Vir collaborated with GlaxoSmithKline to make various refinements to S309, resulting in sotrovimab.Sotrovimab has been engineered to possess an Fc LS mutation (M428L/N434S) that confers enhanced binding to the neonatal Fc receptor resulting in an extended half-life and potentially enhanced drug distribution to the lungs.Sotrovimab has demonstrated activity via two antiviral mechanisms in vitro, antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Clinical efficacy
The pivotal COMET-ICE study is an ongoing, randomized, double-blind, placebo-controlled study to assess the safety and efficacy of sotrovimab in adults with confirmed COVID-19 (mild, early disease with less than five days of symptoms) at risk of disease progression.An interim analysis of this study reported that sotrovimab reduced the risk of hospitalization for more than 24 hours or death by 85% compared with placebo. Overall 1% of people receiving sotrovimab died or required hospitalization for more than 24 hours compared to 7% of people treated with placebo.