By Jeffrey Eiden, MD & Leah Eiden, MD
Family Medicine 
Vaccine.
The word on everyone's lips these days. As family physicians working during a pandemic, we find ourselves studying the specifics of the COVID-19 vaccines and passing the information on to our patients, answering questions, giving advice, and discounting misinformation. Here is what we've been sharing.

First, a quick word about vaccines in general: vaccines are intended to alert the body's immune system to potential infection, to allow the immune system to develop memory that will lead to a stronger defense when exposure to the actual virus or bacteria occurs. In most cases, this promotes such a robust response to subsequent exposure that infection is squelched. The virus or bacteria never gets a foothold to allow it to replicate enough to cause any issues. Vaccines do this by presenting a non-infective look at the virus or bacteria.

At present, there are two vaccines approved for COVID-19. Both of these show the body the spike protein of the SARS-CoV2 (the virus that causes COVID-19) as their way of alerting the immune system. The visual representations of SARS-CoV2 show it covered in red spikes – these are the spike proteins that are targeted by the vaccines. 

Both vaccines use messenger RNA. Messenger RNA enters the body cells but does not enter the cells' nucleus, where the DNA is stored. Once in the cell, the messenger RNA is decoded and informs the production of the spike protein by the cell's own protein production apparatus. After this, the messenger RNA is quickly destroyed. The spike protein moves to the cell surface, where it is then visible to the immune cells. The immune cells make specific antibodies that match the spike protein and allow for the rapid destruction of cells displaying it in the future. Both the Pfizer and Moderna vaccines have shown great effectiveness in preventing COVID19 with this process.

Both of these now-approved vaccines require two doses, the Pfizer vaccine two doses three weeks apart, and the Moderna vaccine two doses four weeks apart. The two vaccines cannot be mixed and matched; both doses need to be the same vaccine. As the immune system is processing the vaccine, there can be related symptoms, similar to those experienced with an immune response to other infections. Specifically, some people have aching muscles, low-grade fever, and fatigue that can last for several days. 

At this point, the most concerning side effect of the Pfizer vaccine, which has been administered to the public over the last week, is anaphylaxis, a severe allergic reaction. There have been six cases of anaphylaxis documented thus far. This is being addressed by cautious observation of patients for up to 30 minutes after receiving the vaccine and by recommending that people who have had issues with anaphylaxis previously avoid this vaccine or at least use even more caution when receiving it. 

That leads to a discussion of safety. There is a lot of talk in the public and social media about safety concerns. The vaccine development process, while completed in record time, did not shorten or cut corners on the investigation of efficacy or safety. Both of these vaccines have gone through the standard testing protocols, which are used to evaluate the safety of new vaccines. Because of the urgency, it was not difficult to recruit the large numbers of people needed to participate in the clinical studies. The data gained from those studies have been carefully reviewed and can be trusted. The first study subjects received vaccine or placebo in August, so any effect of the vaccines after 3 or 4 months is unknown; however, the nature of how vaccines work and the fact that they are not dosed repeatedly limit adverse effects to the short term. 

There is much more that could be said to help you understand what is being offered in these COVID-19 vaccines, but all of it can be summed up with this advice: when you can, get the vaccine. These vaccines work, they are safe and COVID-19 is a serious illness that needs to be stopped. We and our family will be immunized as soon as it is our turn.