CLINICAL MATTER

Last week’s case summary of Covid cases confirmed what most of us have been hoping for. Despite the recent rise in cases and the bogeyman of a new variant (Arcturus), we are not going back to the dark ages of lockdowns and forced quarantines. Cases of Covid from this latest wave of cases have peaked, there have been very few deaths, and less than one percent of cases were severe. BA.1.16 (Arcturus) had nothing to do with the case increases either. The latest genome sequencing showed only 17 out of 279 samples were BA.1.16 and it does not seem to be much of a survival advantage over the other circulating Omicron sublineages. The bump in cases was likely due to a combination of increased mobility during Holy Week, plus the continued relaxation of mandates, and not from a new variant. Case increases will be expected to occur periodically without much danger and with predictable impacts. Our healthcare system will not be threatened and we can remain open, thanks to vaccination and the continued voluntary judicious use of masks.
It is important to note that the Covid cases showing up in the official report represent only a fraction of those who are infected. Nevertheless, cases that are missed and don’t get tested are most likely mild or asymptomatic infections. Transmission doesn’t progress as much as before because most people are vaccinated and their immune systems can cope. The most critical aspect of these numbers is the healthcare utilization rate. No matter how good or bad testing coverage has become, people with severe Covid will still show up at the hospital if they aren’t doing well. They will get tested and they will occupy a hospital bed. No matter how many mild cases you don’t test, these missed cases usually won’t have severe disease and they won’t clog up our hospitals.
Let’s review the natural history of Covid in the last three years. The likelihood of severe disease and the risk of dying from Covid has changed dramatically for the better. This is why we don’t need drastic measures anymore. At the start of the pandemic in 2020, the observed mortality rate of Covid across all ages was one percent. This was more than 10 times the mortality from seasonal influenza.
One percent mortality doesn’t sound like such a large number, until you realize that Covid is a respiratory illness that is easily transmitted between people. Ebola, with its scary 50 percent mortality, gives people a lot of nightmares but it is spread very inefficiently though bodily secretions. A very contagious disease that is easily transmitted with a relatively low mortality rate has the potential to kill many more people than a very deadly disease that is localized and not as transmissible. Covid hit the proverbial sweet spot of being very transmissible. It was deadly enough to kill millions of people. Worse, the mortality rate is 10 times higher for elderly people and those with comorbid conditions compared to the general population. One out of 10 people in these vulnerable populations died prior to the availability of vaccines. Most pandemic restrictions were designed to save these at-risk persons.
Even after vaccination, there is still some residual risk of dying for the elderly and those with comorbid illnesses. Across the board, vaccination reduced the mortality of Covid by a whopping 10-fold from baseline. Therefore, an 80-year-old patient infected with SARS-CoV-2 goes from a 10 percent risk of dying from Covid pre-vaccination down to one percent following vaccination and boosting. A Covid infected healthy 28-year-old patient’s risk of dying was one percent pre-vaccination and became 0.1 percent after vaccination. Looking at these numbers, a vaccinated elderly person is still at the same residual risk of dying as an unvaccinated young healthy individual. This doesn’t even take into consideration the risk of hospitalization and possible complications of severe Covid. This is why doctors still advocate for mask-wearing among the elderly and the chronically ill, along with their household contacts who might infect them. The table here summarizes how the risk has evolved before and after widespread vaccination.

If the vulnerable populations even after vaccination are still in some danger, what else can we do to protect them? Antiviral medications play a significant role in mitigating the risk for severe disease in these groups. Given early, either nirmatrelvir/ritonavir (Paxlovid) or remdesivir can decrease the risk of progression to severe disease by more than 87 percent in vulnerable populations. Molnupiravir doesn’t seem to work as well (risk reduction is only 37 percent), but it can be given if the other antivirals are not available. For patients who develop severe disease despite all these interventions, the use of steroids such as dexamethasone along with immunomodulators, such as baricitinib and tocilizumab, plus remdesivir further cuts the risk of dying by one third.
The decision of the World Health Organization to lift the global public health emergency was made possible through the combined effect of all these different interventions. Covid has become much less deadly thanks to vaccines. Residual risk is still there for the vulnerable populations, but they are not helpless. There are effective treatments for those with breakthrough infection. Elderly people and those with comorbid conditions should strongly consider continuing to use the personal protections that have served us so well throughout the pandemic. In the new normal, an abundance of caution to balance out any uncertainty ensures the best possible outcome.