Omicrone crosses its limit????
The presence of Omicron in genome-sequenced samples in India has crossed 50% (but recently it starts dipping) indicating that the variant is rapidly replacing Delta as the dominant strain. Around 80% of Covid cases among international arrivals are of Omicron, pointing to its wide footprint……
By Abhigyan/Abhinav
According to NICD data there are two clear trends that can be read from Omicron hotspot Gauteng province: First, the share of Covid-positive hospital patients requiring intensive care and ventilators is markedly lower when compared to the beginning of the Delta variant wave; and second, the overall number of people testing positive for Covid-19 is now close to levels seen during the Delta wave at the same phase of the wave, but intensive care unit admissions have not risen in lockstep.
According to Professor of Excellence Dr A K Agarwal, Medical Advisor, Innovation and Clinical Research, Apollo Hospital, New Delhi, says that this mirrors a recent assessment by the NICD that found that this time, most of the hospitalized people are being treated on “room air” instead of needing oxygen support. If these trends hold up for another week or two, Omicron may indeed be considered a milder variant. At present, the conclusion may be tenuous since there seems to be a larger share of younger people infected in Gauteng.
Dr A K Agarwal, Medical Advisor, Innovation and Clinical Research, Apollo Hospital, New Delhi, said, “Two scientific studies reinforce what is being observed. The first, one of the earliest neutralization tests from which results seem to be available, was by GlaxoSmithKline’s biotech arm Vir Biotechnology, which found the company’s antibody treatment is still effective against the full combination of mutations in Omicron.
Dr Suneela Garg, Advisor, ICMR and Director Professor, Department of Community Medicine, Maulana Azad medical College, New Delhi, said, “The study, data for which was not yet out as on Tuesday, found there was a less than threefold drop in neutralisation by the company’s product sotrovimab of an engineered virus with the same configuration as Omicron.The second is new protein modeling by researchers from University of North Carolina, who used the AlphaFold2 deep learning model to create a simulation of the variant. Using what they found, and additional simulations of how known antibodies interact with the virus, the researchers predicted that there are “some structural changes in the receptor-binding domain that may reduce antibody interaction, but no drastic changes that would completely evade existing neutralizing antibodies (and therefore current vaccines)”.
The findings are significant since AlphaFold2, a machine learning protein modelling programme created by Google’s DeepMind, has previously shown unprecedented accuracy in determining how proteins fold, a visualisation that is a challenge to estimate from merely reading genomic data.
According to Dr Amitav Banerjee, Prof and Head, and Clinical Epidemiologist, Department of Community Medicine, Dr DY Patil Medical College, Pune, Omicron’s sequence was shared on November 22, South African authorities reported its spread on November 25, and it was designated a variant of concern on November 26. It is still early days for conclusive signs, but the early hopeful clues may not be entirely misleading.
Data on clinical severity of patients infected with Omicron are increasingly available. Epidemiological trends continue to show a decoupling between incident cases, hospital admissions and deaths, compared to epidemic waves due to previous variants. This is likely due to a combination of the lower intrinsic severity of Omicron, as suggested by a number of studies from different settings, and that vaccine effectiveness is more preserved against severe disease than against infection.
However, high levels of hospital and ICU admission are nevertheless being reported in most countries, given that levels of transmission are higher than ever seen before during the pandemic. Moreover, more data are needed to better understand how clinical markers of severity – such as the use of oxygen, mechanical ventilation, and number of deaths are associated with Omicron.
Dr Amitav Banerjee, Prof and Head, and Clinical Epidemiologist, Department of Community Medicine, Dr DY Patil Medical College, Pune, said, “This is particularly important given that current evidence about severity and hospitalization has largely been shared from countries with high levels of population immunity, and there remains uncertainty about the severity of Omicron in populations with both lower vaccination coverage and lower prior exposure to other variants. The diagnostic accuracy of routinely used PCR and the WHO emergency use listing (EUL) approved antigen detection rapid diagnostic tests (Ag-RDT) assays does not appear to be significantly impacted by Omicron; studies of the comparative sensitivity of Ag-RDTs are ongoing.
Dr Girdhar Gyani, Director General, Association of Healthcare Providers India, said, “ Most Omicron variant sequences reported include a deletion in the S gene, which can cause an S gene target failure (SGTF) in some PCR assays. As a growing minority of publicly shared sequences (including all BA.2 sub lineage sequences) lack this deletion, using SGTF as proxy marker to screen for Omicron will miss Omicron lineages lacking this deletion. Impact on immunity (following infection or vaccination) . Current evidence consistently shows a reduction in neutralizing titres against Omicron in individuals who have received a primary vaccination series or in those who have had prior SARS-CoV-2 infection. In addition, increased risk of reinjection has been reported by South Africa, the United Kingdom, Denmark, and Israel.”
“Undoubtedly, there is a growing body of evidence on vaccine effectiveness (VE) for Omicron, with data available from 15 observational studies from five countries (the United Kingdom, Denmark, Canada, South Africa, and the United States of America), evaluating four vaccines (mRNA vaccines, Ad26.COV2.S, and AstraZeneca-Vaxzevria). Available preliminary data should be interpreted with caution because the designs may be subject to selection bias and the results are based on relatively small numbers. Early data suggest that the effectiveness of studied vaccines is significantly lower against Omicron infection and symptomatic disease compared to Delta, with homologous and heterologous booster doses increasing vaccine effectiveness,” Dr Girdhar Gyani, saiod.
Despite this, follow-up time after booster dosesfor most studies is short, and there is evidence of waning of VE in months following booster doses. VE estimates against severe outcomes, usually defined as hospitalization, are lower for Omicron than Delta, but mostly remain greater than 50% after the primary series and improve with a booster dose to above 80%. More data are needed to assess these preliminary findings across studies, vaccine platforms and dosing regimens. There are no effectiveness data for several vaccines, particularly the inactivated vaccines.
WHO recommends a risk-based, pragmatic approach for Member States to consider when introducing any changes to existing CT and quarantine measures, taking into account the continuity of the critical functions in society and the public health risks and benefits in relation to the pandemic. Any curtailing of CT or quarantine will increase the risk of onward transmission and must be weighed against pragmatic needs.
Prioritization for identification and follow-up of contacts should be given to those at highest risk of getting infected and highest risk of spreading the virus to vulnerable people; and those at highest risk for development of severe disease. Shortening of quarantine of contacts may be considered, in particular for essential workers, including health workers, when combined with rigorous application of infection prevention and control and public health and social measures; and with SARS-CoV-2 testing, when possible.
Travel-related measures A risk-based approach to adjust international travel measures in a timely manner is recommended. See WHO advice for international traffic in relation to the SARS-CoV-2 Omicron variant (3) for additional information. Blanket travel bans will not prevent international spread of any variant of SARS-CoV-2, including Omicron, and can place a heavy burden on lives and livelihoods. In addition, they can adversely impact global health efforts during a pandemic by disincentivizing countries to report and share epidemiological and sequencing data. Health system readiness and responsiveness.
WHO asks all Member States to regularly reassess and revise national plans based on their current situation and national capacities. In anticipation of increased COVID-19 caseloads and associated pressure on the health system (many of which are significantly overburdened after two years of the COVID-19 pandemic), ensure mitigation plans are in place to maintain essential health services and that necessary health care resources are in place to respond to potential surges. This would include surge capacity plans for health workers as well as plans for providing additional practical support to health workers, with particular attention to the needs of mothers and single parent families.
Dr Suneela Garg says that the Clinical care of patients with COVID-19, infected with any SARS-CoV-2 variant, should be administered within health systems according to evidence-based guidelines, such as the WHO living guidelines for clinical management (4) and therapeutics (5), adapted appropriately for local context and resource settings. Risk communication and community engagement
Ensure early warning systems are in place to inform efficient and rational adjustment of public health and social measures, with effective approaches for engaging affected communities and communicating these adjustments while anticipating populations’ concerns.
Authorities should regularly communicate evidence-based information on Omicron and other circulating variants and potential implications for the public in a timely and transparent manner, including what is known, what remains unknown and what is being done by responsible authorities. Communication should emphasise the likelihood that we will learn more and the guidance may change.
Individuals and communities should be provided with timely, accessible and accurate information about how to protect themselves and others from Omicron and other variants, with an emphasis on getting fully vaccinated and continuing to practice protective behaviours to reduce transmission and infection. B.4. Priority research needed
Studies are needed to better understand the properties of BA.2, including comparative assessments of BA.2 and BA.1 for key characteristics such as transmissibility, immune escape and virulence.
Surveillance should continue to be enhanced, including increasing testing and sequencing efforts to better understand circulating SARS-CoV-2 variants, including Omicron and its sub-lineages. Where capacity exists, countries should perform field investigations such as household transmission studies (6), “first few” cases studies contact follow up, and laboratory assessments, to improve understanding of the epidemiological characteristics of Omicron in various settings. The epidemiological studies and sequencing of specimens can be targeted to those with particular individual-level characteristics (e.g. suspected reinjection’s, clinical characteristics, immune compromised patients and selective sequencing of vaccine breakthrough) as well as regular clusters and super-spreading event.
In the current scenario when the third wave of COVID with its new variant – Omicron has been in full swing, near to attaining its peak, this is the most informative and a must-watch video for everyone as it reveals the preventive as well as curative tips because Dr Shashank R Joshi (Padma Shri Awardee), Endocrinologist , said, “Omicron is a nose and throat disease, not a lung disease. while Delta is a lung disease. Delta can kill; Omicron is unlikely to kill. Thus, no need to panic be attentive, preventive and vigilant.
Dr Joshi says that What is the status of Omicron in India and how we can break its virality chain? What is the virulence of Omicron in India as 80 – 95% of patients get no or mild symptoms; 14-4% experience severe symptoms, and 5-1% need ICU care and so on? How do evidence-based medicines work? How COVID Care Vital-7 works and the essence of home isolation? What are the stages when 650 mg Paracetamol works and when other pills work? How misinformation on social media increases complications. How Omicron patients below 60 years with no comorbidities can start symptomatic treatment with paracetamol? When to consult a doctor; get the test done and who should be admitted?n How and when to use monoclonal antibody, Antiviral Pill – Molnupiravir Pill? What are the stages to use Remdesivir? How newer antivirals such as Molnupiravir and Paxlovid are emerging? How the new-age antiviral treatment drugs like Molnupiravir are broad-spectrum antiviral which act as chain-terminators, reducing 30 per cent of hospitalization risk? How the treatment methodology varies for symptomatic and asymptomatic patients and how to save lives?