Omicron, another chapter in the Covid-19 pandemic

Before the winter holidays, a new, more transmissible variant was discovered. By now, Omicron is responsible for most new infections in Europe. What do we know so far? And what are the future possible scenarios?

What do we know about Omicron?

In the meantime, by January 2022, Covid-19 has affected over 315 million people worldwide, killing more than 5 million in its wake. Since discovering the original SARS-CoV-2 virus at the end of 2019 in Wuhan, we have experienced several waves of the disease led by different versions of the virus, the so-called variants, each with its own peculiarities and associated challenges. The latest one, SARS-CoV-2 variant B.1.1.529, also called Omicron, was designated as a variant of concern by the World Health Organization (WHO) on 26 November 2021. First reported in South Africa, since then it has expanded throughout the globe and displaced Delta as the dominant variant globally. However, although Omicron is much more transmissible than earlier-emerging variants like Delta, preliminary studies indicate that Omicron has a decreased ability to infect lung tissue, which may be a reason why it appears to cause a milder infections than Delta.

Ole HeuerDr Ole Heuer, Public Health Emergency Manager for the Covid-19 pandemic at the European Centre for Disease Prevention and Control (ECDC): “By 21 January 2022, there were more than 150000 reported Omicron infections in the European Union and the Euro Area (EU/EA) territory, a higher number of cases than ever seen before, with presence of the variant in all EU/EA countries. However, in previous waves we first observed an increasing tendency in the number of infected people soon followed by a corresponding increase in mortality, and now with Omicron, we are seeing a much higher increase in the number of cases than before, but this is not followed by an increasing death rate.”Read the full interview of Ole Heuer

Omicron accumulates more than 30 mutations in the spike protein, key for the initial steps of infection. That might explain why with Omicron there is a higher ability to evade immunity, which probably then leads to higher risk of reinfection than with previous variants (5.4-fold higher) and vaccines appear to have reduced effectiveness against infection and symptomatic disease, even while still protecting against severe disease.

Sylvie BriandDr Sylvie Briand, Director of the Epidemic and Pandemic Preparedness and Prevention department at the WHO: “We need to remember the importance of achieving the current vaccines, it was unprecedented in the speed at which they were developed and the efficacy they have shown in avoiding death and severe disease. However, all vaccines were developed based on the initial SARS-CoV-2, therefore, to increase the efficacy against new variants, developing new vaccines against other antigens is already a work in progress.”Read the full interview of Sylvie Briand

However, despite its shortcomings, vaccination still appears to be the key to the management of the pandemic, particularly to protect at-risk populations and safeguard the maintenance of functioning health systems.

Dr Ole Heuer: “Although hospitalisations due to Omicron appear to be rising, ICU occupation is not increasing. However, even if milder, the sheer number of cases needing assistance might overload the healthcare systems, increasing collateral risk. To prevent this from happening, vaccines are the most efficient means to try and control the spread of the pandemic and its effects.”

What kind of future awaits us with Covid-19?

It is hard to imagine a life without Covid-19. We are all uncertain whether masks will become an ever-present companion, whether a yearly vaccination will become the norm, and whether travelling without concerns is a thing of the past. It is unlikely that we will see the end of Covid-19 during 2022.

Dr Ole Heuer: “This year, we will probably see a peak of infections at different times in different countries. Then, assuming there is some seasonality in the occurrence of the virus, we may see a decrease during the summer like in the previous summer periods. However, we also need to be vigilant of the possibility of new variants appearing.”

Nevertheless, entertaining various likely scenarios might help us prepare for the future. As we have learned from the first wave, a global response to a pandemic cannot be improvised, and already having a blueprint of possible paths gives a certain security that everything will eventually be alright.

Dr Sylvie Briand: “First scenario, the virus might evolve towards becoming similar to the other four known coronaviruses circulating, and which produce mild disease. In the second scenario, we can imagine a flu like situation. Where there would be outbreaks at certain times of the year. Depending on population immunity, these outbreaks would be dangerous for at risk groups so excessive transmission should be avoided as well as serious health effects. The third scenario is a worst-case scenario, where we would get a completely new variant, very transmissible and very virulent, and forcing us back to square on.”

Useful link:
Enhancing response to Omicron SARS-CoV-2 variant

Related content:
A scientist’s opinion: Interview with Sylvie Briand on the Omicron
A scientist’s opinion: Interview with Ole Heuer on the Omicron

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