Omicron is highly transmissible; it extensively evades neutralising antibody immunity elicited by vaccination and previous SARS-CoV-2 infection. However, there is some good news.

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A small (not peer-reviewed) study of 33 vaccinated and an equal number of unvaccinated persons by scientists in the African Health Research Institute suggested that Omicron could displace the Delta variant because infection by Omicron boosts immunity to the older variant.

The neutralisation of Omicron increased 14-fold over 14 days after the enrolment; also, there was a 4.4-fold increase in the neutralisation of the Delta variant. "The increase in Delta variant neutralisation in individuals infected with Omicron may result in a decreased ability of Delta to re-infect those individuals. Along with emerging data indicating that Omicron, at this time in the pandemic, is less pathogenic than Delta, such an outcome may have positive implications in terms of decreasing the COVID-19 burden of severe disease." the researchers claimed.

Are we seeing light at the end of the tunnel?

On 29 December 2021, media reports quoted World Health Organization (WHO)'s warning that Omicron still poses a “very high" risk and could overwhelm healthcare systems across the world. The highly transmissible variant has taken COVID-19 cases worldwide above 1 million for a second straight day.

Dr Tedros Ghebreyesus, the Director General of WHO, expressed his concern that the simultaneous circulation of Delta and Omicron variants of the coronavirus is creating a "tsunami of cases". Meanwhile, the endless debates with expert participation in mass media leave the discerning viewers baffled. No one knows for sure the true behaviour of this little beast. Researchers are still learning! However, the need for strictly following COVID norms continues to be universally relevant.

A paper titled "Characteristics and Outcomes of Hospitalized Patients in South Africa During the COVID-19 Omicron Wave Compared With Previous Waves" published in the Journal of The American Medical Association (JAMA) by the researchers from South Africa on 30 December 2021 gave very interesting insights. The paper is a preprint. It is not peer-reviewed.

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On November 24, 2021, researchers from South Africa reported the presence of Omicron. The WHO labelled it as a Variant of Concern (VOC) two days later. This variant has shown a very large number of mutations, especially more than 30 on the viral spike protein, which is the key target of the immune response.

Methods

The researchers were from Netcare Ltd, South Africa, a private health care group consisting of 49 acute care hospitals with more than 10,000 beds across the nation. They accessed vast amounts of data collected during the upsurge of hospitalised COVID-19 patients in a series of "waves". They assessed the patients with a positive SARS-CoV-2 test result during the fourth wave and compared the results with those from the previous waves.

Netcare tests all admitted patients for COVID-19 with reverse transcriptase–polymerase chain reaction or, from wave 2 onward, a rapid antigen test obtained from a nasopharyngeal swab. They included all patients hospitalised with positive COVID-19 results. The researchers extracted from the electronic administration system, patient characteristics such as the need for oxygen supply and mechanical ventilation, admission to intensive care, length of stay (LOS), and mortality rates. Follow-up was through December 20, 2021.

South Africa has experienced three COVID-19 waves:

1. June to August 2020 (ancestral variant)
2. November 2020 to January 2021 (Beta)
3. May to September 2021 (Delta)

The new surge started from the beginning of November 15, 2021, coinciding with the identification of Omicron. As of December 7, 26% of community positivity rates were reached. The researchers identified the period when 26% positivity rates were reached in the previous waves (wave 1: June 14 to July 6, 2020; wave 2: December 1-23, 2020; wave 3: June 1-23, 2021) and compared them with the fourth wave (November 15 to December 7, 2021).

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Results

The researchers found that the number of patients treated in the hospitals during the same early period of each wave differed (2351 in wave 4 vs maximum 6342 in wave 3). However, hospitals admitted 68% to 69% of patients presenting to the emergency department with a positive COVID-19 in the first 3 waves vs 41.3% in wave 4

Patients hospitalised during wave 4 were younger (median age, 36 years vs maximum 59 years in wave 3) with a higher proportion of females. The researchers noted that hospitals admitted significantly fewer patients with co-morbidities in wave 4, and the proportion presenting with an acute respiratory condition was lower (31.6% in wave 4 vs maximum 91.2% in wave 3,).

The study gave very interesting insights.

• Of 971 patients admitted in wave 4, 24.2% were vaccinated, 66.4% were unvaccinated, and vaccination status was unknown for 9.4%
• The proportion of patients requiring oxygen therapy significantly decreased (17.6% in wave 4 vs 74% in wave 3) as did the percentage receiving mechanical ventilation
• Admission to intensive care was 18.5% in wave 4 vs 29.9% in wave 3
• The median length of stay (LOS), (between 7 and 8 days in previous waves) decreased to 3 days in wave 4
• The death rate was between 19.7% in wave 1 and 29.1% in wave 3 and decreased to 2.7% in wave 4

Overall, the researchers observed a different pattern of characteristics and outcomes in patients hospitalised with COVID-19 in the early phase of the fourth wave compared with earlier waves in South Africa, with younger patients having less co-morbidity, fewer hospitalisations and respiratory diagnoses, and a decrease in severity and mortality.

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Limitations of the study

The researchers identified many limitations of the study:

1. Firstly, patients’ virus genotyping was not available. The researchers estimated that the Omicron variant to be 81% of the variants isolated by November and 95% isolated by December 2021.
2. Second, hospitals admitted 7% of the patients as of December 20.
3. Third, patients’ behaviour and the profile of admissions could have differed between waves as the authorities implemented different national restrictions and lockdowns. These factors should not have affected urgent admissions.
4. Fourth, patients admitted for COVID-19 could not be differentiated from asymptomatic patients admitted for other diagnoses with an incidental positive test result, and this likely differed between waves, suggested by the lower proportion admitted with respiratory diagnoses in wave 4.

Researchers suggested further research to find out whether the differences between waves are affected by preexisting acquired or natural immunity (44.3% of the adult South African population was vaccinated as of December 2021 and >50% of the population has had previous exposure to SARS-CoV-2 ) or if Omicron may be less pathogenic than previous variants.

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The present status of the virus

On 28 November 2021, WHO noted that it is not yet clear whether Omicron is more transmissible (e.g., more easily spread from person to person) compared to other variants, including Delta. "The number of people testing positive has risen in areas of South Africa affected by this variant, but epidemiologic studies are underway to understand if it is because of Omicron or other factors," WHO added

The WHO conceded that it is not yet clear whether infection with Omicron causes more severe disease compared to infections with other variants, including Delta. "Preliminary data suggests that there are increasing rates of hospitalisation in South Africa, but this may be due to increasing overall numbers of people becoming infected, rather than a result of specific infection with Omicron." WHO clarified.

While explaining that there is currently no information to suggest that symptoms associated with Omicron are different from those from other variants, the WHO cautioned that the initially reported infections were among university students—younger individuals who tend to have more mild disease—but understanding the level of severity of the Omicron variant will take days to weeks. "All variants of COVID-19, including the Delta variant that is dominant worldwide, can cause severe disease or death, in particular for the most vulnerable people, and thus prevention is always key.," the WHO warned.

According to the WHO, the preliminary evidence suggested that there may be an increased risk of re-infection with Omicron (i.e., people who have previously had COVID-19 could become re-infected more easily with Omicron), as compared to other variants of concern, but the information is limited and more information on this will become available in the coming days and weeks.

WHO is coordinating with several researchers around the world to better understand Omicron. Studies currently underway or underway shortly include assessments of transmissibility, the severity of infection (including symptoms), the performance of vaccines and diagnostic tests, and the effectiveness of treatments.

The WHO has not updated its earlier statements as of January 2, 2022.

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Omicron in India

On 31 December 2021, the BBC reported a sharp rise in COVID-19 cases in India over the past week. "It has sparked fears that a third wave, driven by Omicron, is around the corner. The country reported 16,764 new infections and 220 deaths on January 7 for the last 24 hours- the highest single-day increase in cases since October. "The jump appears to be the starkest in densely packed metros such as the national capital, Delhi, financial hub Mumbai and Kolkata city." the news agency added.

As per the "COVID-19 update" posted by the Ministry of Health and Family Welfare on 2 January 2022, the number of Omicron cases in India to date is 1525. Maharashtra leads the pack with 460 cases; Delhi: 351; Gujarat: 136; Tamil Nadu: 117 and Kerala: 109; 10 States (8 to 69 cases); Seven States/UTs report less than a handful of cases (one to 3).

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Legal framework

India has a robust legal framework in place for enforcing orders on COVID-19. Government of India issues such orders under the relevant Sections of the Disaster Management Act 2005 (DM Act). Noting the initial signs of a surge in cases of COVID-19 as well as increased detection of 'Omicron', in different parts of the country, the Ministry of Health and Family Welfare (MOHFW) on December 21, 2021, issued an advisory to all the States and Union Territories prescribing a normative framework for taking evidence-based containment measures at district and local level.

The National Disaster Management Authority (NDMA) exercising powers under the relevant Section of the DM Act has directed the Union Home Secretary to issue an Order for containment of COVID-19 in the country. (The NDMA, chaired by the Prime Minister has four Members) .

The home secretary in turn has directed the state/UT governments and state/UT authorities to consider the implementation of the normative framework as conveyed in the MOHFW advisory dated 21 December 2021 until 31.01.2022. The home secretary also directed that all the district Magistrates shall strictly enforce the suggested measures and proposed using Section 144 of the Criminal Procedure Code for enforcing social distancing.

The Union Home Secretary sent the directives to the Secretaries of Ministries and Departments of Government of India and the Chief Secretaries and Administrators of the States and Union Territories. In spite of having good legal support, enforcement appears to be suboptimal.

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Omicron status in the USA

The US Centers for Disease Control and Prevention (CDC) identified the first confirmed Omicron case in the USA on December 1, 2021. As of December 20, 2021, specialists have detected Omicron in most states and territories. The virus is rapidly increasing the proportion of COVID-19 cases it is causing.

In an update published on 20 December 2021, the CDC stated thus:

"Infections with the recently identified Omicron variant of SARS-CoV-2, the virus that causes COVID-19, are exponentially increasing in multiple countries. Increases in infections are most likely due to a combination of two factors: increased transmissibility and the ability of the variant to evade immunity conferred by past infection or vaccination (i.e., immune evasion). Though the precise contribution of each of the two factors remains unknown, a substantial degree of immune evasion is likely as has been demonstrated in early in vitro studies."

The CDC's analysis showed that current increases in Omicron cases are likely to lead to a national surge in the coming weeks with peak daily numbers of new infections that could exceed previous peaks. The agency expects that specialists may realise these scenarios as soon as January.

In scenarios with lower immune evasion, a surge is still likely, but the peak could be lower and begin as late as April 2022. The CDC also expects surges of hospital demand even if the severity is reduced, because of the large number of anticipated cases occurring in a short period.

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Omicron in Europe

In an update published on 15 December 2021 the European Centre for Disease Prevention and Control stated that between 14 and 15 December 2021, it confirmed 502 additional cases of Omicron in the European Union and European Economic Area (EU/EEA) contributing to an overall total of 2629 confirmed cases so far. The Centre noted that information from public sources have reported confirmed cases by 27 EU/EEA countries.

Overall, there were 10,150 confirmed cases globally, reported by 80 countries. As of 16 December 2021, specialists have identified the Omicron variant in 89 countries across all six WHO regions.

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Omicron in the UK

On 13 December 2021, the UK Health Security Agency reported one Omicron-related death- a case diagnosed in a hospital. On December 24, the British Medical Journal (The BMJ) reported that admission in hospitals is 50-70% less likely with Omicron than delta, but transmission is a major concern.

On December 30, the BMJ noted the Government announcement that it will set up temporary hubs on the grounds of eight hospitals around England as a precaution against a potential surge in admissions due to the current record number of COVID-19 infections.

The “Nightingale hubs” will be able to take around 100 patients each, and construction will start in the first week of 2022 as part of preparations for a potential wave of admissions with the omicron variant.

"The hubs would be expected to take patients who are not fit for discharge but need minimal support and monitoring while recovering from illness, such as people recovering from COVID-19 who are no longer infectious and do not need intensive oxygen therapy." the BMJ report clarified.

This proactive action by the British Government is not surprising. The BMJ revealed that as of 29 December, the UK reported 183 037 new cases of COVID-19, with a seven day average of 118 000 new cases a day to 21 December.

The absence of qualified staff is a major issue in the UK. The BMJ quoted Vishal Sharma, chair of the BMA’s Consultants Committee as saying that there are already over 100 000 staff vacancies in the NHS, and they do not simply have a bank of spare doctors waiting to take up jobs. To compound the problem, thousands of healthcare workers are currently infected with COVID-19 and have to isolate. Obviously, the government has to consider the ground reality!

“The government needs to be absolutely clear about how these Nightingale sites will operate, where the staff might come from, and what the impact could be on other healthcare services if doctors and other healthcare professionals are to be diverted from providing non-COVID care and services.” Dr. Vishal Sharma cautioned

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

Dr K S Parthasarathy is a former Secretary of the Atomic Energy Regulatory Board and a former Raja Ramanna Fellow, Department of Atomic Energy. A Ph. D. from the University of Leeds, UK, he is a medical physicist with specialisation in radiation safety and regulatory matters. He was a Research Associate at the University of Virginia Medical Centre, Charlottesville, USA. He served the International Atomic Energy Agency as an expert and member in some of its Technical and Advisory Committees.