COVID-19 Omicron May Be More Infectious, Deadlier Than Delta

The world’s swift and urgent reaction to the appearance of the Omicron variant might be an indication of just what sort of threat this new iteration of COVID-19 presents. As countries race to stop Omicron—or B.1.1.529—initial data available from the South African National Institute for Communicable Diseases show the concern to be well-founded. Omicron appears to be much more transmissible than the Delta variant. It is already spreading around the globe and is reported to be increasing exponentially in regions where it has taken hold. The epicenter of the Omicron variant is in Gauteng Province, South Africa. As can be seen from the graph below, hospitalizations tripled in just 2 weeks.

Source: South African National Institute for Communicable Diseases – Data for Gauteng Province

Almost 10% of those hospitalized in Gauteng Province (610) are in the ICU, with almost 20% requiring oxygen and 3.8% on the ventilator. It is not known if all of these patients have the Omicron variant, but the increase in hospitalizations is a major concern. In Kentucky, (where this author lives), 818 individuals are hospitalized with 25% of those in the ICU and 13% on the ventilator. However, in Gauteng Province, South Africa, only 20% of those hospitalized require oxygen, and that may be an indication that they have a much lower threshold for hospitalization than in the United States.

Kevin Kavanagh, MD

The Omicron variant has over 30 mutations of its spike protein, which has raised concerns that it may evade the vaccine and monoclonal antibody treatments. Vaccines are likely to retain some efficacy and boosters are critical to increase antibody responses in both vaccinated and those with previous viral infections. A recent preprint study published on medRxiv by Alexis R. Demonbreun, et al., has found that post second dosage of their vaccination, those with previous COVID-19 saw anti-spike proteins increased over 30 times. Vaccinated patients who did not have COVID-19 had a 25-fold increase in antibodies post-booster. It is hoped that a portion of these antibodies will also be active against Omicron. However, monoclonal antibody efficacy may not fare as well since they are composed of only 1 type of antibody or 2 in the case of cocktails.

If the Omicron variant evades immunity, antiviral medications will become of prime importance. Initial reports regarding Pfizer’s protease inhibitor, paxlovid, has observed over an 89% efficacy in avoidance of hospitalizations and no deaths have occurred. Merck’s new medication, molnupiravir, has not fared as well with a reduction in its efficacy in avoidance of hospitalizations of 30%. Since the mechanism of action for these medications is not based on the spike protein, their efficacy should not be affected with the emergence of new variants.

The emergence of the variant in South Africa underscores the importance of vaccinating the entire world. South Africa has only 24% of its country fully vaccinated. However, distribution is a major problem. According to Scott Gottlieb, MD, former FDA commissioner, South Africa has over 30 million doses; only 19 million have been administered. Gottlieb also believes that Omicron is already in the US.

As an initial goal in coping with COVID-19, we must prevent our health care system from being overrun. If the infectivity, lethality, and immune avoidance of the Omicron variant is confirmed, it will be of utmost importance that all who can, become vaccinated, including those who have had past COVID-19. Our pharmaceutical giants need time to manufacture and distribute antivirals along with developing a new vaccine, if one is needed. Travel bans are not designed to stop spread, but to delay the buildup of disease, buying time so countermeasures can be enacted. In addition, strict following of public health measures, with use of N95 masks, upgrading indoor ventilation along with frequent testing is of utmost importance. For the long-term we need to come to grips with the reality that this virus is here to stay and we must change the way we live. This includes expanded curbside and home delivery services along with avoidance of gathering in poorly ventilated settings with strangers.