COVID-19 therapies have similar effectiveness against Omicron and Delta variants

The Omicron variant of SARS-CoV-2 has become the dominant strain of COVID-19 cases over the past few weeks. Compared to its predecessors, the Omicron variant is more transmissible and has created a surge of infections across the globe.

Although some experts claim that the infection caused by the Omicron variant is less severe than that caused by the Delta variant, COVID vaccines may not be as effective against Omicron infection.^1,2 

Antibody therapies and other antiviral drugs for treating COVID-19 have been approved or are currently under study. However, the use of these treatments may not be the same for the Omicron variant as they are for the Delta. 

This study used eight anti-COVID medications, representing a broad range of treatment mechanisms. An example of one drug tested is Remdesivir, which inhibits viral replication mechanisms.³ 

The effect of these medications on cells infected with either Omicron or Delta SARS-CoV-2 isolate was observed. 

Omicron infected fewer cell cultures than the Delta variant, while similar infection rates were found in one cell line. Due to the differences in these cell lines and the immune proteins that they express, the study suggests that the Omicron variant may be less effective at infecting cells with this specific immune response – interferon response. 

According to the researchers, this study provides “for the first time an explanation, why Omicron infections are less likely to cause severe disease. This is due to Omicron, in contrast to Delta, does not effectively inhibit the host cell interferon immune response,“⁴ – Professor Martin Michaelis of the University of Kent. 

Omicron and Delta showed similar sensitivity to COVID therapies

Of the eight types of anti-COVID drugs tested, the effect on Omicron infection did not differ significantly from Delta.³ This suggests that the variance between the two viral SARS-CoV-2 strains did not change the effect of a broad range of COVID-19 therapies. 

Professor Jindrich Cinatl of Goethe-University added, “Although cell culture experiments do not exactly reflect the more complex situation in a patient, our data provide encouraging evidence that the available antiviral COVID-19 drugs are also effective against Omicron.”⁴

References

1. Planas, D. et al. (2021). Considerable escape of SARS-CoV-2 Omicron to antibody neutralization. Nature. Doi: 10.1038/s41586-021-04389-z. ​​
2. Collie, S. et al. (2021). Effectiveness of BNT162b2 Vaccine against Omicron Variant in South Africa. The New England Journal of Medicine. Doi: 10.1056/NEJMc2119270.
3. Bojkova, D. et al. (2022). Reduced interferon antagonism but similar drug sensitivity in Omicron variant compared to Delta variant of SARS-CoV-2 isolates. Cell Research. Doi: 10.1038/s41422-022-00619-9. 
4. Bernards, M. (2022). Researchers of the University fo Kent and Goethe-University Frankfurt find explanation why the Omicron variant causes less severe disease. Accessed Jan 27 2022. Retrieved from https://www.eurekalert.org/news-releases/940979. 
5. Image by Gerd Altmann from Pixabay