Editor’s Note: This Q&A was adapted from Calle 24’s Aug. 16 episode of Cafecito con El Doctor, where Dr. Carina Márquez and Dr. Joe Derisi discuss the delta variant, vaccine safety, and the current state of Covid-19. Due to space, this interview has been condensed. To listen to this conversation in its entirety, visit Calle 24’s instagram page at @calle24_sf.
What exactly is a variant of a virus?
JD: That’s a great question and it can be confusing sometimes with how it’s portrayed in the media and so on. But what variant refers to is a mutation, a change in the genetic code of the virus that produces a difference in how the virus might behave or act, or might change a protein. So all of these viruses copy their genetic code when they replicate and they make mistakes. They’re not perfect. And when they make mistakes they can introduce mutations that change the sequence of their proteins in their RNA and that sometimes can lead to new functions or now abilities. Like maybe being a little bit more transmissible for example. It can also go the other way. Sometimes mutations can hurt the virus. And so when people say ‘a variant,’ they really mean a particular mutation in a particular virus.
Is the Delta variant more contagious than the other strains?
JD: Yes. The data thus far from numerous countries, England, Israel, many others that have a lead on their epidemiology does show the Delta variant to be more transmissible. Now the exact percentage tends to vary depending on how you look at it. But I think it’s safe to assume the Delta variant is in fact more transmissible. And to really get to your point, if we look at all the different variants that were in the United States just four or five months ago, they’re essentially all gone. We’re really just left with the Delta variant and a couple other related strains that are similar. So that fact alone suggests that it’s more transmissible. There’s really nothing else but Delta anymore.
Why should I get a booster shot if I already received the Johnson & Johnson vaccine?
CM: As you all probably have heard, the San Francisco Department of Public Health is allowing sites, like Unidos en Salud and other sites in the city, to give a supplemental dose and that is for a few different reasons. The thought is that if you get a second booster with an mRNA vaccine, that will increase your immunity especially for the Delta variant. And we are able to offer that right here at our site at 24th and Capp Streets.
Will Moderna and Pfizer offer boosters for their vaccines?
CM: COVID changes so fast, and so all of the information about the vaccines, about how they perform against each variant and how long they last, we’re continually updating and getting more information. And so I think that is a question that we’re actively studying. We don’t have that answered yet, but it’s something under active study. But what we do know is that the FDA just approved third booster shots for people who are immunocompromised. These are people who are getting chemotherapy for cancer, who had an organ transplant, who are on medicines that suppress the immune system. A third shot can help boost that immune response. So the FDA and the CDC has said ‘yes, they need that extra third shot.’ And so we are waiting for further information from the San Francisco Department Public Health here on that. As we keep getting more information and real-world data, I think one of the things that as a doctor that has really stuck out to me is that over and over and over again the vaccines have proven to be very protective against severe disease. And keeping people out of the hospital, keeping them off of the ventilator, preventing death. And so those have been shown over and over again in many studies in many countries, and so that is something that I think is consistent and really reassuring and I think it’s helping us a lot, especially in San Francisco. While we do have rising hospitalizations, I think it would be much worse if we didn’t have such a high vaccination rate.
JD: And I’ll just add to that. The vaccinations are super important. Does it mean that if you’re vaccinated, that you can go around without a mask and that you won’t get infected? Well that’s not true. We have seen plenty of infections among people who are fully vaccinated. And so you might ask, why does it matter then? Well it matters because those people who are fully vaccinated generally have either no symptoms or mild symptoms and they don’t go to the hospital. By and large the people that are ending up in the ICUs now are the unvaccinated.
Why are unvaccinated people at greater risk?
JD: That’s a multifactorial question. An unvaccinated pool of people in the population is like an available pool that the virus can get into and replicate and spread with greater freedom. And the more infections that the virus can undergo, the more chance that you get new variants. Because there’s this probability that it makes mistakes every time it replicates. So the more we allow it to spread, and it spreads better in unvaccinated people, the more chance that we get new mutations and new variants that then we have to deal with again. So protecting everybody and keeping them out of the ICU is number one. But number two, the unvaccinated can also threaten those around them. That it’s not just you, it’s everybody around you. As I said, vaccinated people can get this as well, even though they will be protected from severe disease.