Former US Secretary of State Colin Powell died on Monday of Covid-19 complications. His family announced that he was fully vaccinated. He was 84 years old, and had multiple myeloma, a blood cancer. Health officials worry that anti-vaccine activists will seize upon Powell's death to make the claim that vaccines don't work, reports CNN. If you can still die after being vaccinated for Covid-19, what's the point of getting the vaccine? CNN discussed the question with Dr. Leana Wen, an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She is also author of a new book, "Lifelines: A Doctor's Journey in the Fight for Public Health." CNN: When we see vaccinated people dying from Covid-19, how do you explain that vaccines are still worth taking? Dr. Leana Wen: We need to start with the science and what the research shows. The Covid-19 vaccines are extraordinarily effective in preventing illness and especially severe disease. The most recent data from the US Centers for Disease Control and Prevention shows that they reduce the likelihood of testing positive for Covid-19 by six-fold and the likelihood of death by 11-fold. That means that if you are vaccinated, you are six times less likely to get Covid-19 than someone who's unvaccinated. And you are 11 times less likely to die from Covid-19 compared to an unvaccinated person. That's really excellent. However, the Covid-19 vaccines do not protect you 100%. No vaccine does, just likely virtually no medical treatment is 100% effective. That doesn't mean the vaccine doesn't work, or that you shouldn't take it. CNN: Are some people more likely to have severe outcomes from Covid-19, despite vaccination? Wen: Yes, and based on what have learned, General Powell fell into that category. We know that individuals who are older and have underlying medical conditions are more likely to suffer severe illness and to die following breakthrough infections. Those at particular risk are people who are immunocompromised. Having multiple myeloma would put General Powell into this category, and, in addition to his older age, would add to the level of risk. Note that this is one of the reasons booster shots are being recommended. Back in August, federal health officials recommended that people with moderate or severe immunocompromise, who had the Pfizer or Moderna vaccines, receive a third dose of the vaccine. They warned that even with the additional dose, immunocompromised individuals should take additional precautions. That's because this is a category of people who are particularly susceptible to severe outcomes. CNN: You've said before that vaccines work best when everyone takes them, right? Wen: Exactly. Think of the Covid-19 vaccine as a very good raincoat. It works very well to protect you in a drizzle. But if you're in a thunderstorm, and then a hurricane comes, there's a much greater chance that you'll get wet. That doesn't mean your raincoat is defective. It means that you are in bad weather, and the raincoat alone may not always protect you. If you are around a lot of virus, that increases your chance of getting infected. The problem isn't the vaccine -- it's that there is too much virus around you. That's why the key is to get as many people vaccinated as possible. That reduces the overall rate of infection and ends up protecting everyone. And, if you are in an area with a lot of virus, wearing a mask in indoor crowded spaces adds an additional level of protection. And let's not forget that we also get vaccinated to protect the most vulnerable among us, who are at the highest risk for severe outcomes. A study of 13 states over six months showed that fully vaccinated individuals made up only 4% of all hospitalizations from Covid-19. Unvaccinated people are 17 times more likely to be hospitalized for coronavirus than fully vaccinated adults, according to that CDC study. Those who end up with breakthrough cases resulting in hospitalization are more likely to be older and to have multiple underlying medical conditions, as we discussed. CNN: What are other things you would say to those who don't believe the vaccine is effective? Wen: I'd ask them to think about other aspects of medicine. Let's say that someone has heart disease. There are medications to treat heart disease, but they aren't 100% effective -- nothing is. Just because someone ends up with an exacerbation of their disease and in the hospital, doesn't mean that the medications aren't worth taking. Or let's use an example of prevention. Let's say that someone who eats a healthy diet and exercises a lot still ends up with high blood pressure and diabetes. That doesn't mean diet and exercise aren't good to do. It just means that you can take all the right steps to prevent a disease, but sometimes you still could get the disease. One of the main conundrums in public health is that the work we do is about prevention. While you see the end result if and when prevention fails, you don't see all the lives saved because of prevention. A modeling study supported by the National Institutes of Health found that the Covid-19 vaccines prevented more than 139,000 deaths in the first five months they were available. By May 9, around 570,000 Covid-19 deaths had occurred in the United States. Without vaccines, 709,000 deaths could have happened. The bottom line is that vaccines work. They reduce the likelihood of contracting disease and of getting severely ill and dying. They are not 100% because nothing is. CNN: Can vaccines can also prevent a resurgence of the virus this winter? Wen: Yes. It's encouraging that Covid-19 infection numbers are falling from the terrible delta wave that consumed the country this summer. However, another wave of infections is possible, especially with only 57% of the US population fully vaccinated. I agree with Dr. Anthony Fauci, who said this weekend that "it's going to be within our capability to prevent that from happening ...The degree to which we continue to come down in that slope will depend on how well we do about getting more people vaccinated." Ultimately, the key to reducing everyone's risk from Covid-19 -- and to ending the pandemic -- is for all of us to get vaccinated. This protects us, and those around us.