5 Questions on the Delta Variant

A highly transmittable form of COVID-19 known as the Delta variant is spreading globally, bringing with it new fear and uncertainty. Some may be questioning the efficacy of the vaccines or feel hesitant to return to stricter COVID-19 protocols.

We want to answer all your questions and dispel any myths, so I sat down with Dr. John Greene, chair of the Infectious Diseases Program at Moffitt Cancer Center to discuss the new variant and how you can best protect yourself.

Hwu: What are we seeing locally and nationally with the Delta variant?

Greene: The Delta variant is about 60% more transmissible than the original variant. It has not been proven to be more virulent, but it quickly has spread throughout the United States. Currently, 83% of all COVID-19 infections are the Delta variant.

The next big question is how well it is covered by the vaccines and it looks like Pfizer, instead of being 95% protective for the original variant, is about 88% protective after the second dose. Moderna is thought to be about 72% and the Johnson and Johnson vaccine is believed to be about 65% to 70% protective against illness. A lot of people though can actually still get a mild illness, so the vaccine is preventing them from being hospitalized. The unvaccinated are the ones who are bearing the brunt of the Delta variant; however, there are breakthroughs of a mild nature in the vaccinated.

Hwu: What percentage of people in the country are now vaccinated who are eligible?

Greene: Right now, in the state of Florida 48% of the population is vaccinated and in Hillsborough County we're at 52%. The rest of the United States is close to 50% and some states are doing incredibly well like Vermont, which is around 70% to 80%. The lowest vaccination rates tend to be mostly in the south, where the numbers are in the 20^th, 30^th, 40^th and occasionally 50^th percentile, so Florida is sort of in the middle compared to the other states.

Hwu: What would you say to those who are worried about the vaccine side effects?

Greene: The chances of having a COVID-19 illness severe enough to cause hospitalization, ventilator support and even death is so much higher than having a side effect from vaccination. Side effects can include mild local pain at the injection site, flu-like illness because your immune system is revved up and then the extremely, extremely rare events we saw with the Johnson and Johnson vaccine with blood clots. The chance of an adverse event from a vaccine is very tiny and the chance of a severe COVID-19 illness is significant. A lot of younger people are saying they won’t get vaccinated because we know the young don’t get that sick, but if you go to the hospitals you will see among those hospitalized are 20-year-olds, 30-year-olds and 40-year-olds. The reality is that you need to get vaccinated because you could become severely ill and deal with the prolonged COVID-19 symptoms where some people can feel very ill or tired for six months or more.

Hwu: When will a vaccine booster be available?

Greene: We’re all eagerly waiting for this meeting between Pfizer, the Centers for Disease Control, U.S. Food and Drug Administration and the vaccination boards. They claim that there'll be something officially coming out within one to two weeks. I think it’s safe to say if you are immune suppressed because we know your immune system does not make enough antibody, that third booster could get you to a high enough level to prevent infection, including the Delta variant. So as far as opening it up to other groups, that is a debatable topic. What is the downside? To me it’s very minimal. I would get the booster right now because I want my titer to be as high as possible to prevent infection. When all the data is in they will probably come out with a recommendation, similar to the flu, where every year you will get a vaccine. I believe that is where we are headed.

A new study found that while Pfizer’s COVID-19 vaccine continues to show strong protection against serious illness and hospitalization after six months, protection against the virus appears to wane after half a year. The data shows the overall effectiveness of the vaccine fell from 96% to 84%, and that a third booster dose increases antibody levels against the Delta variant by more than five times compared to levels after a second dose.

Hwu: Should those who have had COVID-19 get vaccinated?

Greene: There's been raging debate about whether you should be vaccinated if you have already been infected and have antibodies/immunity from COVID-19. The logic is that your antibody titers may not last as long as the vaccination, and you may not have as high of a titer to prevent variants, such as the Delta variant. So even if you have been infected, you should get the vaccine to boost your titer so you can have the best immunity to prevent any variant.