What to know about the Delta variant
Dr. Jose Mercado, associate hospital epidemiologist at Dartmouth-Hitchcock Medical Center, answered questions about the Delta variant of Covid.
How concerned should we be about the Delta variant?
The Delta variant [is] classified as a variant of concern [and] is now the predominantly circulating variant in the United States. One thing that we are quite sure of is the increased transmissibility of the disease — the likelihood of one person infecting other individuals who are so susceptible to the disease — compared to the original strain. The thing that we still don’t know is the likelihood of the Delta variant causing severe disease and hospitalizations. We assume that it is more likely, but we need more data around that.
How prevalent is it in New Hampshire?
We do not routinely test … each positive test to confirm the variant … [but] there is a proportion of [positive tests] that the state [has tested for the variant], just to confirm the epidemiology of the disease … and what we’re seeing thus far is consistent with what we’re seeing in the nation: The Delta variant appears to be becoming, if not already, the predominantly circulating variant in our communities.
Does it spread the same way as the original strain?
The belief is that it still is spread through respiratory droplets. You may catch it when you are close to an individual who has the infection who is breathing out air that you are then inhaling … or is coughing and sneezing around you … or if you have [infected] respiratory droplets in your hands that you then transfer to your nose and mouth. The debate is whether it has the ability to spread as an aerosol — the difference between droplets and aerosol is the distance of how the virus can spread between individuals — and I don’t think we have necessarily confirmed that.
Who is at the highest risk of contracting it?
Unvaccinated individuals are at highest risk for acquiring a virus … and our elderly population and those who may have a weak immune system remain at the highest risk of severe disease.
How effective is the vaccine at protecting against the Delta variant?
The most recent data that we have received [from] the CDC is that the vaccine [initially] provided greater than 90 percent protection, [but] for new infections over time, we did see a slight drop in vaccine effectiveness … to about 80 percent. What is reassuring is that vaccine effectiveness against hospitalizations and severe disease has remained above 90 percent over time and with the introduction of new variants.
Does that mean Covid cases are trending up overall?
Most counties in the state are … at high levels of transmission. If you compare where we were back in the spring, where we started to see a drop, we’re now seeing an uptick of cases as we go into the fall.
Should vaccinated individuals continue practicing mitigation strategies?
Yes. … Now is really not the time to completely relax our mitigation strategies. … Data [shows that] even vaccinated individuals have the same amount of viral loads, compared to unvaccinated individuals, meaning they can still transmit the disease. … Following the CDC guidelines of wearing our masks, [practicing] hand hygiene and physically distancing when we’re not able to wear our masks is important for protecting individuals who are not vaccinated or have weak immune systems.
What is the current data on positive cases among children?
We are seeing more cases as well as more cases that lead to hospitalizations in children. This may be driven by [the fact that] kids younger than 12 years old are still part of our unvaccinated population. The hope is that, as the vaccine is approved for the younger population, that will start to help curb the rise in cases in younger individuals.
Are you anticipating a spike in cases among kids as they return to school?
Not if we’re able to follow the mitigation strategies. … When we resumed in-person learning, we were successful in keeping our kids safe, and it didn’t really result in a lot of outbreaks. … Data [showed] that exposures [among children] really came from community exposures, not exposures at school. … That’s why it’s important to continue to follow those mitigation strategies to reduce your risk of exposing yourself [and] potentially bringing it home.
Featured photo: Dr. Jose Mercado. Courtesy photo.