Coronavirus US: can the second dose be different from the first?
The two-dose covid-19 mRNA vaccines are not interchangeable and each should be taken at a specified interval to ensure they are as effective as possible.
Currently there are three covid-19 vaccines being administered in the US. The Pfizer-BioNTech and Moderna are the only two mRNA covid-19 vaccines approved for emergency use and both require two doses. In order to get the most protection from either of the vaccines you will need to receive both doses but they are not interchangeable.
Different vaccines use different methods to teach the body to how to create the antibodies needed to fight off a virus when it enters the body. The covid-19 vaccines created by Pfizer-BioNTech and Moderna use a new method which utilize messenger RNA (mRNA) to get the body’s cells to produce the spike protein the coronavirus uses to attach to cells, but not the virus itself, so that the it will trigger the immune response in the body.
Pfizer-BioNTech and Moderna are given at different intervals
Both the Pfizer-BioNTech and Moderna have different intervals for when the second dose should be administered. It takes the body about two weeks after the first dose to build initial immunity against the covid-19, but the second dose boosts that immunity to reach the approximately 95 percent effectiveness reported in clinical trials.
The two doses of Pfizer-BioNTech should be given 21 days apart and Moderna 28 days apart but no sooner according to the Center for Disease Control and Prevention (CDC). However, it is possible to get covid-19 before or just after vaccination as the body hasn’t had time enough to develop the necessary immune response. In the event that you get sick from covid-19 between doses you should hold off getting the second dose until you have finished your isolation period but it is important that you reschedule for your second jab.
It is important to get both doses of the two-dose vaccines
Should you miss your appointment for the second dose for whatever reason, you should reschedule as soon as possible. The CDC recommends not waiting longer than six weeks or 42 days after the first dose. When you get your first dose of the covid-19 vaccine, someone at the location that administers the vaccine will give you a vaccination card with the information about which vaccine you received.
Because the two vaccines are not the same you will want to hold on to that card in case you have the second dose administered at a different location to ensure that you get a second dose of the same vaccine. Perhaps even take a picture of it just in case, however, health officials warn not to share that picture on social media to avoid people copying your vaccination card. In the future, your vaccination card may be asked for to confirm vaccination for travel or to enter businesses.
You are not considered fully vaccinated until two weeks after your second dose of either the Pfizer-BioNTech and Moderna covid-19 vaccine. Likewise, you must wait two weeks after the single dose of the Johnson & Johnson covid-19 vaccine to be fully vaccinated.
You should get the second dose even if you have side effects, unless a medical professional says otherwise
A vaccine is designed to produce an immune response, so experiencing side effects are common and temporary. Each person reacts differently so some experience side effects but some don’t. The CDC says that even if you have side effects after the first shot, you should get your second shot. That is unless a vaccination provider or your doctor tells you not to get it.
Some of the temporary side effects that you may experience
In the arm where you got the shot:
Throughout the rest of your body: