Summer is upon us, and the COVID-19 pandemic has grown long in the tooth.
The coronavirus, SARS-CoV-2, has been responsible for the worst global pandemic in more than a century. It may yet have some bite left, unless we can more fully deploy our best defense.
The story of the pandemic has become one of vaccines and variants. The one offers hope for a final exit strategy. The other poses renewed risk for new surges in cases, hospitalizations and deaths, especially among the most vulnerable – the unvaccinated.
Variants result from the inevitable mutations of a virus that is freely spreading and infecting susceptible people. Many of these mutations have little or no impact, while others confer benefits to the virus. In the latter category of mutations are what scientists call virulence factors. This means that the advantage gained by the virus strengthens it in some way.
The Centers for Disease Control and Prevention has identified six so-called variants of concern. The CDC says a variant of concern is one for which there is evidence of an increase in one or more of these factors: transmissibility, more severe disease, decreased protection from previous infection or vaccination, reduced effectiveness of treatments or vaccines, or viral testing failures.
The most recently identified variant of concern is the Delta variant, which arose on the Indian subcontinent and has become the dominant strain in multiple countries, including the United Kingdom.
Evidence suggests that the Delta variant has about 60% more efficient transmission than earlier variants, with rates of infection doubling every seven to 10 days. It also appears more severe, causing twice the rate of significant infections that require hospitalization. As of last week, it accounted for 10% of new cases in the United States and 25% of new cases in Colorado.
The good news is that the Delta variant, like the other variants of concern, seems to respond well to current vaccines, provided people are fully vaccinated. Among fully vaccinated people, the risk of symptomatic infection with the Delta variant is reduced by about 88%, while the risk of hospitalization is reduced by 96%. However, a single dose of the two dose COVID-19 vaccines (Pfizer and Moderna) does not provide the same benefit.
The narrative of the COVID-19 pandemic is increasingly becoming one of two populations. Those who are fully vaccinated appear to be protected and are increasingly returning to normal routines. Those who are unvaccinated remain not only at risk but likely at increased risk from the developing variants of the virus.
For this latter group, a return to surges in viral infections and serious illness is anticipated in the coming weeks and months, unless we can collectively ramp up vaccine acceptance and vaccinations.
It is clearly a matter of personal choice. But the impact of the choice is becoming clearer as well.
We are slowly approaching a full vaccination rate of about half of the eligible U.S. population (those age 12 and older). The best hope for the other half is to roll up their sleeves and get the vaccine.
Dr. Matthew A. Clark is a board-certified physician in internal medicine and pediatrics practicing at the Ute Mountain Ute Health Center in Towaoc.
