Viruses constantly change through mutation and sometimes these mutations result in a new variant of the virus. Some variants emerge and disappear while others persist. New variants will always continue to emerge. The CDC and other public health organizations monitor all variants of the virus that causes COVID-19 in the United States and globally. Currently, the CDC is working with state and local public health officials to monitor the spread of the Omicron Variant. As of December 20, 2021, Omicron has been detected in most states and territories and is rapidly increasing the proportion of COVID-19 cases it is causing.
The rapid emergence of the Omicron variant is a stark reminder of the ongoing threat posed by the evolution of the COVID-19 pandemic and reinforces the critical need to achieve high levels of immunization coverage in all countries, including in highly vulnerable populations, in a timely manner.
The Centers for Disease Control and Prevention (CDC) has identified the potential for a rapid increase in infections of the new variant of SARS-CoV-2, the Omicron variant, in the United States. 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). The rapid growth rate in Omicron infections is believed to result from a combination of increased transmissibility and the ability to evade immunity conferred by past infection or vaccination (i.e., immune evasion)
The clinical severity profile of Omicron infection will strongly influence its impact on future U.S. hospitalizations and deaths. At present, early data suggest Omicron infection might be less severe than infection with prior variants; however, reliable data on clinical severity is limited. Even if the proportion of infections associated with severe outcomes is lower than with previous variants, given the likely increase in the number of infections, the absolute numbers of people with severe outcomes could be substantial.
Initial Identification of Omicron
First identified in Botswana and South Africa in November, the Omicron variant (named by the WHO using the Greek alphabet – Alpha, Beta, Gamma, Delta and so on) has surged around the world over the past few weeks. The World Health Organization designated Omicron a “variant of
concern” on Nov. 26, warning that the global risks posed by it were “very high.” Since then, the variant has been identified in more than 90 countries. By Dec. 18, the Centers for Disease Control estimated that it made up 73 percent of all new infections in the United States.
Below are some targeted bullet points with answers to specific Omicron questions as reported by the NY Times on December 23, 2021:
Does Omicron Spread Faster Than Other Variants?
Yes – It is two to three times as likely to spread as Delta.
Does Immunity from Previous Infections Stop Omicron?
While it likely provides protection against severe disease, immunity from previous infections does little to hinder infections with Omicron. The first clues that Omicron could evade immunity came from South Africa, where scientists estimate that at least 70 percent of people have had Covid-19 at some point in the pandemic. An unexpectedly large fraction of Omicron cases involved people who had previously been infected.
This ability to evade immune defenses is probably part of the explanation as to why Omicron cases are doubling so quickly. While other variants are getting knocked out by antibodies, Omicron is succeeding in infecting more cells — making it more successful at getting into more people.
How Much do Vaccines Protect Against an Omicron Variant Infections?
Several studies indicate that full vaccination plus a booster shot provides strong protection against infection with Omicron. Without a booster, however, two doses of a vaccine like Pfizer-BioNTech’s or Moderna’s provide much less protection. (Still, two doses of a vaccine do appear to protect against severe disease from Omicron.)
Scientists drew blood from fully vaccinated people and mixed their antibodies with Omicron in a petri dish loaded with human cells. Every vaccine tested so far has done a worse job at neutralizing Omicron than other variants. And antibodies from people who received two doses of the AstraZeneca or one dose of Johnson & Johnson vaccines don’t seem to do anything at all against Omicron. But when researchers tested antibodies from people who had received boosters of Moderna or Pfizer-BioNTech vaccines, they saw a different picture. Boosted antibodies blocked many Omicron viruses from infecting cells.
Can Vaccines Reduce the Severity of Covid?
Preliminary studies suggest that they can. In South Africa, researchers who reviewed the first three weeks of Omicron cases in the country’s largest health care system found that two doses of the Pfizer-BioNTech vaccine had effectiveness of 70 percent against hospitalization.
How Bad Will a Covid Case Cause by Omicron Be?
A series of preliminary studies in South Africa, Scotland, and England indicate a lower percentage of Omicron infections are leading to hospitalizations compared to the Delta variant, which was the dominant form of the coronavirus from the summer to December.
Is Covid Caused by Omicron Still Treatable?
Yes. Unfortunately, the government paused the distribution of monoclonal antibodies from Regeneron and Eli Lilly on Dec. 23 because Omicron appears to be resistant against the drugs. But GSK has reported that its formulation, called sotrovimab, will probably remain effective, and the federal government is scrambling to secure more doses.
In late December, the Food and Drug Administration authorized two new antiviral pills for Covid, called Paxlovid and molnupiravir. Preliminary experiments indicate that both should remain effective against Omicron. That’s because the mutations that have made Omicron resistant to monoclonal antibodies do not affect the viral proteins that are targeted by the pills.
What Will Omicron Do Over the Next Few Months?
Researchers are creating mathematical models to figure out what Omicron will do in the months to come. These models, by necessity, are based on assumptions about the variant, and those assumptions may need to be altered as more evidence comes to light. But scientists can already see that Omicron is very transmissible and is adept at evading immune defenses.
Even if Omicron does turn out to be milder than other variants, it could still push hospitals to their limits. A smaller fraction of Omicron cases may require hospitalization, but if the number of Omicron cases is much bigger than in previous surges, there will still be more seriously ill patients to treat. And in the United States, those Omicron cases will stack on top of already high levels of hospitalizations driven by the Delta variant.
A team of modelers who run a project called the Covid-19 Scenario Modeling Hub issued a statement on Dec. 22 making it clear that even as they fine-tuned their projections, the writing was already on the wall. “The best information we have at the moment indicates the threat posed by Omicron is substantial and imminent, and individuals and governments should be prepared to respond accordingly,” they warned.