The world anxiously awaits news of a safe and effective COVID vaccine and the hope of returning to “normal” that it provides. How will we know if a vaccine is safe? How soon can we expect a vaccine to be available to everyone? The following questions and answers will help you understand the steps necessary to create a COVID vaccine and how to get it ready for distribution.

Q: in general, how do clinical trials work?

A: The primary goal of vaccine development is safety. But we also want an effective vaccine to either prevent the disease altogether or at least have the body familiar with the disease to fight it off and make symptoms milder. Historically, vaccine development is a long and arduous process, sometimes taking decades. Once a vaccine is developed it usually enters three stages of trials. The first trial is usually with a very small population to see if the vaccine creates an immune response. The second phase is with a somewhat larger population, sometimes targeting those who are most vulnerable to the illness. Finally, in the third stage, the vaccine is given to larger numbers of people. Efficacy and safety are closely monitored in all three phases. Then, even after the vaccine is approved and released to the public, there are several reporting methods to continue to monitor for side effects and safety.

Q: Naturally, the public will have concerns over the safety of any COVID vaccine.

A: There are several vaccines in the “pipeline” of development and testing. Again, the priority of the Food and Drug Administration is safety. We are in a new experience with the two most recent vaccines from Pfizer and Moderna. They are developed in a unique way using what is called messenger RNA. Trials so far have shown greater than 90% efficacy, which is excellent, but these vaccines have essentially been “fast-tracked” because of the threat of the Pandemic. Keep in mind, the science and technology that has been used in the past to create safe treatments and vaccinations contribute to the development of vaccines like these and to the overall process of meeting safety standards. There are some reports of body aches and other symptoms associated with the vaccine, but they are mild and short-lived, reflecting that the body is responding to the vaccine and creating immunity.

Q: What percentage of the population would need to receive the vaccine for this to provide protection?

A: The percentage of the population to be vaccinated to create greater protection for us all varies from vaccine to vaccine and illness to illness. We don’t quite know yet, but with something like measles, you need greater than 80-85% immunity to prevent outbreaks of the disease. With COVID, some folks have created some immunity by having had the virus and now we will be adding the people who have been vaccinated. What we also don’t know is how long that immunity lasts. There will be a lot of ongoing monitoring of any new vaccine to make the best recommendations.

Q: What portion of the population would need to strongly consider receiving the vaccination?

A: The question of who to vaccinate is very interesting and challenging. Certainly, we want to protect the most vulnerable. Most of the discussion has focused on the elderly and especially those living in assisted living and nursing homes. But front-line health care workers and first responders need to be protected for sure. They encounter sick patients daily. The larger conversation is around children, adolescents and young adults, who although can rarely get sick compared to older adults, are the ones who tend to get infected with the virus, develop, at worst, mild symptoms, and contribute to the spread. Initially, there will be a very limited supply of vaccine, but with hopes of more vaccine becoming available in the future. We will need to prioritize.