On behalf of the Emerging Infectious Disease Task Force
On January 17, 2022, the world experienced around 125 million new cases of the SARS-CoV-2 Omicron variant on a single day, over ten times the previous peak from the massive Delta variant surge in April 2021. The United States has experienced several “million-case days” and continues to set records for new cases every week.
The Institute for Health Metrics and Evaluation forecasts that 50% of the global population will have become infected with SARS-CoV-2 between December 1, 2021, and March 31, 2022. Those are unprecedented case numbers and infection rates for any previously known pandemic agent.
Omicron Variant Is More Contagious
Asymptomatic infections are likely driving much of the Omicron wave. Even with the initial SARS-CoV-2 strains, the rate of asymptomatic infections is thought to have been as high as 40 to 45%. Mounting evidence on Omicron puts the level of asymptomatic infections closer to 80 or 90%. Other likely contributing factors include the way the Omicron virus glycosylates carbohydrates on the cell membrane and enters cells, vaccine efficacy and possible levels of prior COVID-19 immune protection.
SARS-CoV-2 Continues to Evolve
The SARS-CoV-2 virus could become even more dangerous. There are potentially risky genomic mutations in many of the identified variants – including Omicron. These mutations are in locations of the viral genome that are known or suspected to enhance transmission, lethality or other viral activities. These mutations have not yet resulted in widespread expression of these characteristics by Omicron for reasons that are not entirely clear.
A new variant based on a sub-variety of Omicron, the B.1.1.529 – BA.2, may have even higher infectivity, or Ro, than its parent. At the time of writing, it is rapidly replacing Omicron B.1.1.529 – BA.1 in many global locations and has already been detected in the United States. This new subvariant carries the same multiple genomic mutations as the original Omicron variant. Research indicates these mutations may enhance the potential for more serious complications.
SARS-CoV-2 Becoming “Endemic”
We can get a basic idea about endemicity by looking at the plotted case curves for COVID-19 or other pandemics. When a pandemic starts, there are initial spikes in patient numbers, then drops in case numbers to varying degrees followed by intermittent spikes as conditions change or new variants develop.
Highly contagious variants eventually develop to displace almost all the other viral variants. After continued spikes and dips in the curve, a variable baseline of case numbers eventually is reached. That baseline is occasioned by slow increases, decreases and spikes depending on what the virus does and what humans do.
When pathogens like Influenza and the Coronaviruses become endemic, it is difficult to remove them from the human population; however, humans are far from helpless against the SARS-CoV-2 virus. There is much we can do to reduce the impacts of these pathogens once they become endemic.
Ending the Pandemic
It is difficult, and dangerous, to make specific predictions about biology and pandemics. Early on, many experts described the mid-point of the SARS-CoV-2 pandemic around February 2022. However, that will likely be the mid-point from the perspective of historians 20 years from now. This assumes that although we will see occasional spikes in case numbers, we will see a gradual decline of infections over time.
Multiple elements of our interactions with the SARS-CoV-2 virus will occur over the next two years. The virus will become more endemic and less pandemic. We will slowly note a decrease in the daily pressures the virus causes. This battle is far from over, but despite multiple setbacks and a few major advances, we are winning.
Continuing Vital Health Measures and Vaccination
COVID-19 will continue to change and challenge us. There are, however, indications that the pandemic may be turning a corner. Yet, it is critical not to stop doing the things we know curb COVID-19’s effect. We must continue to support and promote COVID-19 vaccination coupled with smart public health measures.
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