CME INDIA Presentation by Dr. Shashank Heda, Founder and Chief Executive, CovidRxExchange (CovidRxExchange is a Global Non-profit Organization registered with the US Govt. Exempt under IRS code 501 C (3), relentlessly working since March 2020, disseminating expertise and insight in the medical care of Covid), Dallas, Texas, US. Email: info@covidrxexchange.org; shashank.heda@covidrxexchange.org.
Key Points
1. Emerging data indicating that Omicron, at this time in the pandemic, is less pathogenic than Delta.
2. Omicron outcome may have positive implications in terms of decreasing the Covid-19 burden of severe disease.
“The increase in Delta variant neutralisation in individuals infected with Omicron may result in decreased ability of Delta to re-infect those individuals. If Omicron does prove to be less pathogenic, then this may show that the course of the pandemic has shifted – Omicron will take over, at least for now, and we may have less disruption of our lives.” – Prof Alex Sigal (Africa Health Research Institute, Durban, South Africa and School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa).
- Omicron infection enhances neutralising immunity against Delta (Collated by CovidRxExchange).
- Infection with the SARS-CoV-2 Omicron variant creates a neutralising immune response against the Delta variant.
- The research team enrolled 15 previously vaccinated and unvaccinated people who were infected with the Omicron variant into the study. They used plasma, a blood product which contains antibodies, from the participants to test the ability of the antibodies to control both Omicron and Delta in the lab – a so-called ‘neutralisation’ test (Collated by CovidRxExchange). They measured this close to when the participants had symptoms, and again around two weeks later.
- The results showed the development of antibody response to Omicron, with neutralisation increasing 14-fold over this time (Collated by CovidRxExchange). However, the team also observed that the participants developed some enhanced immunity against the Delta variant, with Delta neutralisation increasing 4.4-fold. The researchers also show that vaccinated participants were able to mount a better neutralising response against Delta, while the response in unvaccinated participants was more variable.
- “The increase in Delta variant neutralisation in individuals infected with Omicron (Collated by CovidRxExchange) may result in decreased ability of Delta to re-infect those individuals,” said Prof Sigal. “If Omicron does prove to be less pathogenic, then this may show that the course of the pandemic has shifted – Omicron will take over, at least for now, and we may have less disruption of our lives.
- This is a Big News. I shared evidence to support the contention that Omicron infection may actually prevent infection from the dreaded Delta.
- To clarify further, there is no evidence to state that Omicron may herald an end of Epidemic or other variants.
CME INDIA Learning Points
- In South Africa Omicron infections led to a lower incidence of severe disease relative to other variants.
- That Delta and Omicron will interact is still unclear.
- Whole world is excited that Omicron will curtail the spread of Delta by eliciting a neutralizing immune response against Delta in people infected by Omicron
- Alex Sigal, Khadija Khan, Sandile Cele et al isolated Omicron virus without the R346K mutation from an infection in South Africa. This virus had similar neutralization escape.
- They neutralized this isolate with plasma from the blood of 15 participants enrolled during the Omicron infection wave in South Africa, with each participant having a confirmed diagnosis of SARS-CoV-2 by 60 qPCR.
- They used a live virus neutralization assay and calculated the focus reduction neutralization test (FRNT50) value, the inverse of the plasma dilution required for 50% 62 reduction in infection foci.
- It is well known that the ability of one variant to elicit immunity which can cross-neutralize another variant varies by variant.
- Immunity elicited by Delta infection does not cross-neutralize Beta virus and Beta elicited immunity does not cross-neutralize Delta well.
- This is the first study showing that Omicron can displace the Delta variant.
- So, it can elicit immunity which neutralizes Delta – making re-infection with Delta less likely.
- This finding becomes a big news indeed as Omicron escapes neutralizing immunity elicited by Delta and therefore may re-infect Delta infected individuals.
- If Omicron (less pathogenic) displaces mighty Delta, then the incidence of Covid-19 severe disease would be reduced and the next year – 2022 – will be less disruptive to India too.
CME INDIA Tail Piece
References:
1.https://www.ahri.org/omicron-infection-enhances-neutralising-immunity-against-delta/
2.Omicron infection enhances neutralizing immunity against the Delta variant
Khadija Khan, Farina Karim, Sandile Cele, et al.medRxiv 2021.12.27.21268439; doi: https://doi.org/10.1101/2021.12.27.21268439
3. Cele, S. et al. Escape of SARS-CoV-2 501Y.V2 from neutralization by convalescent plasma. Nature 593, 142-146, doi:10.1038/s41586-021-03471-w (2021).
4. Moyo-Gwete, T. et al. Cross-Reactive Neutralizing Antibody Responses Elicited by SARS-CoV261 2 501Y.V2 (B.1.351). N Engl J Med 384, 2161-2163, doi:10.1056/NEJMc2104192 (2021). 262 11
5. Greaney, A. J. et al. A SARS-CoV-2 variant elicits an antibody response with a shifted immunodominance hierarchy. bioRxiv, 2021.2010.2012.464114, 264 doi:10.1101/2021.10.12.464114 (2021).
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Interesting Analysis and wishful thinking
Very good science , authentic, good knowledge sharing, enlightening. Thanks CME India .
Very good analysis sir. Thanks for sharing.
Very useful information and study on omicron.
GOING THE HERD IMMUNITY: OMICRONS
Omicron can produce immunity able to neutralise Delta as well, making re-infection with Delta less likely, whereas immunity from Delta provides only limited protection against Omicron, meaning Omicron may re-infect individuals with a prior Delta infection.
In a paper that is not yet peer reviewed, researchers studied the immunity developed to the latest, highly transmissible, variant of concern – Omicron – in both fully vaccinated and unvaccinated people (a total of 33 participants) in South Africa. They enrolled people soon after the onset of symptoms, during the country’s ongoing Omicron infection wave, and looked at their ability to neutralise both the Omicron and Delta variants of the virus.
After confirming that all the participants were infected with Omicron, the scientists looked at how the antibodies of infected people could neutralise the virus. What they found was that, after 14 days, not only did their ability to neutralise Omicron increase by up to 14.4 times, but so did their ability to neutralise Delta, by as much as 4.4 times. By contrast, say the researchers, infection with Delta does not boost protection against previous variants, like Beta, nor vice versa.
WHAT DOES THIS MEAN
This implies that Omicron can produce immunity able to neutralise Delta as well, making re-infection with Delta less likely, whereas immunity from Delta provides only limited protection against Omicron, meaning Omicron may re-infect individuals with a prior Delta infection. The researchers say “these results are consistent with Omicron displacing the Delta variant”.
There is a caveat, however. The number of people studied here was small and the researchers suggest some might have been previously infected with COVID-19: “Therefore, it is unclear if what we observe is effective cross-neutralisation of Delta virus by Omicron elicited antibodies, or activation of antibody immunity from previous infection and/or vaccination.”
It is still not entirely clear whether Omicron is less pathogenic than Delta, and to what extent. But if it is and if this research bears out, then as Omicron becomes more dominant it could mean that COVID-19 transitions into a less harmful disease, unless another more harmful and more contagious variant emerges that outcompetes Omicron.
Very small sample to get a mention.
Possible because viral epidemics usually end by mutating into less severe variant.
Whether Omicron is that variant or not, GOK