House Call with Carol Hughes

When will there be a vaccine?

As the pandemic moved through its early stages, a lot of hope was placed on the development of a vaccine that would enable us to get back to normal. We were told that it could take longer than a year to arrive at a suitable candidate since there were still no vaccines for SARS or MERS, which are in the same virus family as COVID-19. Despite the tempered prediction, the focused efforts of many researchers and teams in laboratories have come up with a number of candidates for stage three trials.

That means humans are receiving potential vaccines as testing moves from theoretical to practical. It is an incredible development given the speed with which we have arrived at this point. Now we will wait again, as trials determine the efficacy of vaccines and learn about any side effects as well. These potential vaccines will be given to thousands of people during this phase and, although it might be tempting to believe the solution to our problems may be just around the corner, it’s more reasonable to look at this stage as one of seeing a light at the end of a tunnel. We still have a way to go, but we are exceeding some predictions.

You may have heard that trials may have been suspended in this process. If someone inside the trial becomes ill in another way or experiences a potentially negative side-effect during a trial the whole exercise can be suspended while the occurrence is considered. We are told this is normal and often happens during phase three trials. The biggest difference with these and other trials is that so many of us are paying attention to the whole process. Also, it is likely that suspended trials are considered more newsworthy than resumption activities may be.

With potential vaccines undergoing the rigors of phase three trials there is no doubt we have more reason for hope today than we did in March. That doesn’t mean we shouldn’t temper our expectations, however. While trials take time, production and distribution of vaccine doses will take even more time and there are potential stumbling blocks to those goals as well. Consider that a vaccine candidate in the USA which is showing a lot of promise has a unique storage requirement of minus 70 degrees Fahrenheit. The limiting factor in that case is the ability to store and distribute doses since most freezers cannot provide that temperature.

Another factor will be efficacy. For vaccines to be effective, they will have to limit spread across approximately 60 percent of the population. Some vaccines are showing effectiveness that is thought to be in the 60 percent range which would require almost the entire population be vaccinated to achieve the immunity target. Given the growing reluctance for vaccines in the population, it is easy to imagine the challenges associated with any attempt to ensure widespread compliance with official requests to get vaccinated.

It’s not difficult to see where the challenges lay as we move towards a vaccine. Just this week a patient has died in a Brazilian trial showing that although we may be close, there’s no knowing when an effective vaccine will be made available. That said, we have measures available to us that will help relax public health restrictions moving forward. These are the same measures we have used with great effect to this point-limiting contact, physical distancing, wearing masks when sharing enclosed spaces, and maintaining best hygiene with a particular focus on clean hands. The effectiveness of those has already been established and are our best defense for the second wave of the pandemic.