Covid-19: Omicron Update

What I have learned in the first two weeks of the Omicron outbreak

This update was prepared by Dr. Mario Quiros. Board Certified Emergency Medicine Physician

What I have l learned

I just finished working 7 of 8 days in the Emergency Department in Miami, FL and experienced Omicron firsthand. I am writing this update to share what I have learned, hopefully ease some tension, and give readers a realistic expectation of what is to come. Omicron seemed to have hit out of nowhere. We literally went from seeing very little Covid -19 cases at the end of November to being inundated with patients the week of December 13th. All of the sudden several of my friends were getting ill at the same time, nearly all of them vaccinated. At the time it was still felt that the majority of circulating Covid -19 cases were still attributed to Delta, but I knew something different was going on. I have never seen so many completely vaccinated (many with a booster dose), previously infected patients, and patients who had been infected and were also vaccinated become ill in such a short period of time. We knew Omicron was starting to circulate in our communities but the rate it has eclipsed Delta as the dominant strain of Covid-19 in Miami was astonishing. We now know that Omicron makes up over 73% of Covid-19 cases nationwide and over 90% of cases in certain regions. Omicron is likely responsible for 90-95% of Covid-19 cases in Miami-Dade county currently. How is Omicron Different from Delta? Most of my patients have tended to be younger, vaccinated, and/or previously been infected with Covid-19. Typically new waves start in younger healthier populations so we will learn more about how it effects older patients and patient with more co morbidities over the next few weeks. Patients:

1. Generally had mild symptoms compared to the Delta surge over the summer which hit unvaccinated patients particularly hard. However a large proportion of infected patients were fully vaccinated which we did not see with Delta

2. Had more upper respiratory symptoms such as runny nose, congestion, sore throat, laryngitis, burning in the chest, and bronchitis

3. Did not lose their sense of taste and smell like we were seeing commonly with other variants

4. Had little pulmonary (lung) involvement. Less of our coughing patients had pneumonia on their chest X rays or abnormal breath sounds on exam.

5. Were much less likely to be hypoxic (low oxygen levels) compared to prior variants.

6. Omicron patients were more likely to have their asthma exacerbations triggered by their infection Prior strains caused pneumonia at a high rate but normally did not trigger asthma. Omicron has been causing more bronchitis than pneumonia and this bronchial inflammation was triggering patients asthma.

7. Fatigue, body aches, headaches, fever, and chills all remain common symptoms.

The Good News:

1. This is the mildest strain of Covid-19 I have treated to date. So far I have seen less critically ill patients, admitted less patients to the hospital, and far less patients have required supplemental oxygen or any form of ventilatory support.

2. We have more tools than ever before to prevent severe disease in the form of Vaccines that prevent severe illness and Monoclonal antibody therapy to treat patients once they become ill.

3. I think this is going to burn through fairly quickly. Most Delta surges lasted 6-8 weeks. Based on the rate of infection this will probably spread very quickly but hopefully burn through very quickly as well, likely in 2-8 weeks

The Bad News: 1. Omicron appears to be much more contagious than previous strains and seems very effective at evading immunity provided by vaccination. Recent data suggests 2 doses of the Pfizer vaccine is 33% effective at preventing infection compared to the unvaccinated. The protection against hospitalization is 70% compared to being unvaccinated. These numbers are significantly down from what we saw with prior variants, both these numbers were well over 90% previously. Booster doses are recommended at this time to to decrease the chance of infection and severe disease. The exact efficacy is unclear as I have seen conflicting data on 3 dose vaccine efficacy and this is something we are still learning about on a daily basis. The CEO of Pfizer claims 3 doses of Pfizer provides similar immunity to Omicron that 2 doses of Pfizer provided to the original Covid strain. From what I have seen clinically to date this does not correlate but we need more data to know for sure. 2. The timing is terrible, right before the Holidays. When you combine this with how contagious Omicron is and many patients having mild symptoms the chance for widespread transmission is very high. I feel we are only going to learn about the severity of this strain on the high risk population in the next few weeks. Unlike Delta, we are likely to see widespread disease in the elderly population and in patients with more co morbidities as Omicron is very effective at evading immunity provided by the vaccine. We can only hope the symptoms are mild similar to what I have seen in the younger and healthier population. Only time will tell. In the mean time my advice is to practice an abundance of caution for those around you who would be considered high risk from a Covid-19 infection. This disease has humbled us all and I think prudence is the wisest course of action this Holiday Season.