What it tells us about how the omicron is deadly

Recent South African official medical reports and national data on the novel coronavirus disease (COVID-19) have indicated that since early November, when omicron was first detected, cases of COVID-19 have increased considerably. However, most patients had mild symptoms at worst, and cases are now down sharply. These observations differ significantly from previous waves, including those attributed to the delta variant.

Journalists also said that although people who were vaccinated and unvaccinated developed the disease in about equal numbers, most hospital patients were not vaccinated. And although the current wave of COVID-19 in South Africa is drawing to a close, experiences with omicron waves in South Africa could follow very similar patterns in other countries.

Contrary to this relatively encouraging news, some Recent tweets and localized reports suggest that some hospitals in South Africa have seen – or are experiencing – an increasing number of inpatients, with an increasing number of patients requiring treatment in intensive care units and requiring mechanical ventilation – a key indicator of severe COVID-19.

What we need to take into account in the South African data to determine whether omicron was responsible for the recent COVID-19 cases and deaths in South Africa is:

A review of official COVID-19 figures in South Africa from December 1, 2021 to December 21, 2021 shows that new confirmed cases of COVID-19 per million population have increased significantly from 63 to 303 (an increase of 380 %), while the total number of deaths only increased from 0.466 to 0.583, (a 25 percent increase). At the same time, the estimated spread rate of all COVID-19 infections (the R rate) has steadily declined to around 54% of the December 1 value.

Can we be sure that omicron has been a major contributor to the recent South African wave of COVID-19?

Some countries, such as the UK, have substantial national initiatives that monitor the changing genetics of SARS-CoV-2 variants and provide near real-time data to help confirm both variants in patients and map the disease. spread of COVID-19. South Africa, however, currently does not have a similar ability to sequence and track SARS-CoV-2 variants. However, substantial effort and resources have gone into monitoring omicron in South Africa, and the data this has produced is compelling.

Detection of the delta and omicron variants of SARS-CoV-2 in populations, including the UK, however, is only part of an assessment of the possible impact of omicron. While sequenced viral genomes obtained from South Africa, UK and other patients show that the predominant omicron variant circulating in UK and many other countries appears to be very similar in genomic sequence, other factors must be taken into account in determining how omicron infections can develop. in regional populations and individuals.

Similar to other countries including the UK, South Africa recently suffered a significant wave of COVID-19 disease nationwide, attributed to the delta variant. Infections in this delta wave likely helped induce or enhance a substantial amount of naturally acquired immunity to SARS-CoV-2. Has the Delta Wave eased the omicron imperative for everyone?

The level of fully vaccinated South Africans is estimated to be between 26% and 46% of the population, with a significant percentage having received either Johnson & Johnson or Pfizer vaccines. Around 76% of the UK population has had at least one jab, with booster shots also on the rise. The demographics of the South African population and the immunization levels of the general population therefore appear to be significantly different from those of the UK population. Will these factors reduce the lethality of omicron for most of the UK population, and what could this mean for an individual?

What does this mean for the UK?

In the UK, from December 1, 2021 to December 21, 2021, COVID-19 cases per million population rose from 634 to 1,280 (a 101% increase), while the total number of new deaths from COVID-19 actually fell from 1.791 to 1.697 per million (a 5 percent decrease). And R has steadily increased to around 135% of the Dec. 1 starting value.

Patients with severe COVID-19 have two serious negative health effects. First, they can develop a disease of the respiratory system that causes patients to receive more oxygen than normal, sometimes with the added help of mechanical ventilation of a patient’s lungs. They can also develop a “cytokine storm” where a person’s immune system races up and causes damage. These symptoms are seen in delta variant infections and can lead to death or long-term health problems.

It is only when the aggregate data shows a lasting decrease in the course of these diseases in hospitalized patients with infections confirmed by variants of omicron, that we can be sure that omicron is less lethal than delta. The latest British Zoe COVID-19 study (an app-based study to support COVID-19 research) is encouraging, with one in two colds actually being an omicron infection.

On January 21, 2022, the UK Office for National Statistics is expected to release the latest current real-world hospitalization data on the severity of COVID-19 in the UK. These UK data should reflect most of South Africa’s official findings and show that in the UK population omicron causes mild illness.

Decision-makers and citizens rely on precise and clear analysis and advice through data to make the most informed decisions and conclusions. Countries need more time to fully explore omicron variant data before they can finally determine if omicron is less lethal than delta, for everyone, or if other measures are needed to protect people. sensitive.

Correction. A few percentages had come out: “… shows that new confirmed cases of COVID-19 per million inhabitants have increased considerably, from 63 to 303 (an increase of 473%)”. It should read “a 380 percent increase”. And… “the cases of COVID-19 per million inhabitants increased from 634 to 1,280 (an increase of 201%)”. It should read “a 101 percent increase”.

David Pryce, Lecturer in Biomedical Sciences (Immunology), Bangor University

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