CME INDIA Presentation by Admin.
Recombinant variants of SARS-CoV-2 and XBB/XBB.1:
The recent and emerging recombinant variants with large immune evasion potential are a new threat to the world or will they pass silently?
“This pandemic has surprised us before and very well may again.” – Dr. Randeep Guleria.
The new strain is more contagious than any other strain of Covid-19 so far. Hence the resistance is strengthened. About 1.8 per cent of those infected may require hospital treatment. There is no cause for concern at present. But everyone should be careful. Everyone should wear a mask properly for self-protection. Masks must be worn by the elderly and those with co-morbidities: Ministry of health (Kerela).
Pearls from Dr. Rajeev Jayadevan:
| These are immune escape variants. |
| Since Omicron arrived in November 2021, it has been giving off branches that divide into smaller branches. Of these, BA.2 and BA.5 proved stronger than the rest. |
| From BA.2 and BA.5, a series of sublineages kept appearing. |
| Each of these had additional mutations which were concentrated on the RBD or receptor binding domain of the spike protein of the virus. This is the part that the virus uses to attach to the human cell. |
| BA.5.1.7 and BF.7 are names given to downstream descendants of BA.5. |
| There will be periodic regional surges that especially coincide with festivals and group gatherings. |
| Wearing masks Indoors and preferring outdoor to indoor gatherings are safe options. |
| The vulnerable individuals will need to be specially protected. |
Dr. Vijay Arora, Senior Director of Internal Medicine, Max Hospital, Patparganj, New Delhi:
| Omicron new subvariant BF.7 enters India: |
| New wave of coronavirus infection may hit this winter if people aren’t more cautious. |
| This will be fuelled in part by increased social mixing and in part by the multiple emerging Omicron subvariants that are more immune evasive. |
| BF.7, which is a part of BA.2.5.17, is more dangerous and spreads very fast. It escapes immunity and can even infect vaccinated people who have been previously immunized with full doses and boosters. |
What is recombinant Variant?
- Recombinant variants of viruses are generated when two or more viruses co-infect a cell at the same time.
- Chances for co-infection is rare, but nevertheless they occur.
- Genomic surveillance can efficiently pick up such recombinant isolates.
Emerging evidence
- There are 49 odd recombinant variants now catalogued for #SARSCoV2 by @PangoNetwork.
- an open collaboration of scientists across the world.
- PANGO names recombinant variants of #SARSCoV2 with a name starting with ‘X’.
- Of the newer and emerging recombinant lineages, one of the most prominent is XBB.
- XBB is a recombinant lineage between two Omicron Sublineages BJ.1 and BA.2.75.
- BB and its sublineage XBB.1 (with additional S: G252V) have been largely found in Singapore and now in Bangladesh, though also found in across Europe, North America and Asia. To note, Singapore is having an ongoing surge of infections.
Evading Neutralising Antibodies
- The data suggests the variant can evade a wide spectrum of monoclonal antibodies
- One recent preprint research demonstrated that as few as five additional convergent mutations based on BA.5 or BA.2.75 could completely evade most plasma samples, including those from BA.5 breakthrough infection, while retaining sufficient hACE2-binding affinity.
- These results suggest that current herd immunity and BA.5 vaccine boosters may not provide sufficiently broad protection against infection.
- Broad-spectrum SARS-CoV-2 vaccines and NAb drugs development should be of high priority, and the constructed convergent mutants could serve to examine their effectiveness in advance.
- The ability of XBB to evade a wide spectrum of neutralizing antibodies would suggest it could over-power all of the previous variants. Analysis by @rquiroga777suggests XBB along with BQ.1.1 could soon become dominant in the UK.
CME INDIA Discussion:
Dr. Shashank Heda, Texas: What are BQ.1, BQ.1.1, and BF.7?
(Collated by CovidRxExchange) October 19, 2022
- As the United States braces for another wave of COVID-19, a surge in new Omicron subvariants has raised concern among scientists. The U.S. Centres for Disease Control and Prevention released data last week showing that BQ.1 and its sibling BQ.1.1 now account for more than 10 percent of the country’s cases (Collated by CovidRxExchange), while BF.5 accounts for another 5 percent.
- BQ.1, BQ.1.1, and BF.7 are particularly troubling because of some traits they have in common. These subvariants have each developed mutations in the same critical areas of the coronavirus’s protein spike receptor, (Collated by CovidRxExchange) changes that allow the virus to slip past the immune system’s antibodies.
Are the new subvariants more severe?
- Although it’s likely that these subvariants will be better at evading immunity, there’s little evidence to indicate they cause more severe disease than previous variants. these variants might also be able to evade the drugs that are used to treat people (Collated by CovidRxExchange) who are immunocompromised or otherwise susceptible to severe forms of COVID-19. According to Anthony Fauci these variants may elude important monoclonal antibodies” designed to target the same position of the spike protein receptor that has mutated in the new subvariants.
Do vaccines protect against the subvariants?
- In the absence of data, we can’t be sure if the existing bivalent vaccine against Omicron BA.4 and BA. may work against the new subvariants. However, since the new (Collated by CovidRxExchange) subvariants are descendent of BA.5 variant, it may be safe to presume, the existing bivalent vaccines against BA. 5, may be effective.
- What can be our best recourse?
- Masking, sanitation, vaccination, and usual mitigation (Collated by CovidRxExchange) for low to moderate risks are best means of avoiding or controlling the spread of the disease.
Dr. Shashank Joshi, DM Endo, Mumbai:
- Clearly there is more hype around this, basics still remain but the hype is unfounded n unfortunate till we get clinical co relates, hospitalization and mortality data
- So, I feel it’s pre mature to sound alarmist and continue doing simple basics rules of public health hygiene and behaviour
Dr. Shashank Heda, Texas:
- May be the White House has few things to learn from you.
- Fun apart, ours are anecdotal opinion, there’s is data-based analysis.
- Recently, one of India’s authority Dr. Vinod Scaria, who has deep insight on the data from India and globally, commented on the emerging variants. We should rely on that data.
Dr. Shashank Joshi, DM Endo, Mumbai:
- Vinod is well known to all of us, recombinants have been known to all of us since HIV times. He was our collaborator with Dr. Karyekarte when we set up the Maharashtra genome project.
- Honestly basics still prevail but these Omicron-like variants from Singapore to Arkansas need hard public health data corroborations like clinical profile, symptoms, hospitalization and deaths. None of it is available. Also, Singapore most cases evaluated were asymptomatic.
- South Africa is just getting out of winter and nothing unusual typical viruses around the season are profiled.
No Panic or Alarm, Simple Surveillance and Vigilance Most of the current C19 strains are Omicron like which are localized, less virulent and just need careful scrutiny. Science and Research as well as public health surveillance is the key. No Panic please 🙏
We have to be open however that’s how we picked up delta then strong cross talk between clinicians and science professional then.
Dr. Shashank Heda, Texas:
- We should not undervalue the importance of data driven approach. When Fauci talks about an alert, it is data driven. Let’s not panic, underplay or create hype.
- We need to be cautious with our approach, overdoing doesn’t help, underplaying neither does.
- Shashank, If I may ask, where do you see the risk level?
Dr. Shashank Joshi DM Endo, Mumbai:
- Risk level of what? Isolated strain isolation does not mean we have a public health all it tells us is to do more sequencing and currently from a public health standpoint one needs to be alert without being alarmist. I would wait for 2 more weeks to flag a Risk zone current numbers are too small.
- Experts Urge Caution After Detection of Bq.1 Strain –
- This debate is interesting. What is risk zone? Can you explain how that risk zone emanated during the initial phases of Covid during March through June 2020?
Dr. S. K. Gupta, MBBS MD(Med), CFM (France), Senior Consultant Physician, Delhi:
- Conditions of 2020 were different than 2022.
- Agree in totality with Prof Shashank Joshi
- Every new strain Now and then should not lead to pressing Panic Button Similar apprehensions were there for many earlier variants including BA4.,5.
- India passed thru the period peacefully.
- We need to understand that world in 2022 is divided into 3 zones: US and Europe, China and India depending upon the type of vaccines used, exposure level of infection and hence immune imprint. Current variants scaring USA and Fauci are offshoots of BA.5.
- Hope they too pass without much Fuss.
- All that Scares USA may not Dare India Nevertheless we remain watchful
Dr. Urman Dhruv, Consultant Physician, Ahmedabad:
- Question remains Second booster? (4th dose). Yes, 1 year after last infection or 1 year after first booster?
Dr. Alok Rai, Raipur:
- Booster must cover all existing mutants.
Dr. S. K. Gupta, Senior Consultant Physician Hosp, Delhi:
- With current Level of transmission in India risk is extremely low.
- There have been doubts even on the efficacy of 3rd booster (for general population).
- Boosters could be advocated for:
- Elderly.
- Immunocompromised.
- Solid organ transplant recipients.
- And during active Waves when they may boost Nab. Levels and grant some protection.
- Nasal vaccine should be welcome whenever available.
Dr. Urman Dhruv, Ahmedabad:
- For health care professionals.
- Rather than during active wave, before a possible potential active wave.
Dr. S. K. Gupta:
- They have been vaccinated, infected, reinfected, booster vaccinated.
- May be opted as abundance of caution.
Dr. Harish Moorjani, Hudson, USA:
- I agree. No one knows the downside of “over boosting” with the same spike protein antigen. Is there a ceiling effect on the efficacy side? No one knows.
Dr. Raka Sheohare, Diabetologist, Raipur:
- Then it should be smarter than mutants 😃 and then Mutant word will be irrelevant.
CME INDIA Tail-Piece:
References:
- Imprinted SARS-CoV-2 humoral immunity induces convergent Omicron RBD evolutionYunlong Cao, Fanchong Jianet al. bioRxiv 2022.09.15.507787; doi: https://doi.org/10.1101/2022.09.15.507787
- https://m.economictimes.com/epaper/delhicapital/2022/oct/19/pharma-companies/experts-urge-caution-after-detection-of-bq-1-strain/articleshow/94952207.cms?utm_source=whatsapp_pwa&utm_medium=social&utm_campaign=socialsharebuttons
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Covid is over. Experts are holding on to the tail of receding pandemic.
Now a bigger risk entails earth in form if War Famine and Hunger.
XBB variant wave is already on descent in Singapore. In tune with my view.