Is the second strain of COVID-19 causing more severe infections?

Yes, the second strain of COVID-19 is indeed causing more severe infections. Research conducted by a team at Imperial College London and published in the journal Nature Medicine on March 15th 2021 analyzed whole genome sequences from over 19 million SARS-CoV-2 samples collected between December 2019 and February 2021. The results showed that variants in circulation today are significantly more infectious than earlier ones, suggesting that this newer strain is associated with more rapid transmission of the virus as well as higher severity levels among infected patients.

The research also found evidence for increased severity due to new mutations specific to each variant – some causing significant issues such as an increased ability to evade defensive mechanisms like antibodies against previous strains, others having an effect on viral replication rate or cell tropism aiding further spread into susceptible populations. As these mutations continue to accumulate, we may see even greater differences in severity compared to earlier virus variants present at the start of the pandemic.

It's important that research continues so we can better understand how these genetic changes may be impacting disease severities and better prepare ourselves against future outbreaks.