While all three vaccines have some differences, they do share certain features. The most important similarity is that all of these vaccines are safe and effective at preventing symptomatic Covid-19 and have a significant impact on the rates of hospitalizations and death. Because of the seriousness of the pandemic, all three have been given approval through an emergency use authorization from the U.S. Food and Drug Administration. The Pfizer, Moderna and Johnson and Johnson (J&J) vaccines are all administered the same way — through a shot in the arm, and much like other vaccines, they all can have the same mild side effects. You may experience pain, redness or swelling in the arm where you received your shot. There have also been reports of feeling tired, headache, muscle pain, chills, fever and/or nausea among some vaccine recipients. All side effects should be mild enough that they do not interfere with your daily activities and should resolve within a few days — and they're much less serious than the effects of getting Covid-19 itself. It's important to remember that these side effects are not caused by the coronavirus but are caused by your body's immune system response to a foreign protein — and they may mean the vaccine is working. The Centers for Disease Control (CDC) has an app called v-safe that allows you to use your smartphone to check in with the CDC, so it can monitor how you're feeling after you get any of the three available Covid-19 vaccines. None of the three vaccines contain eggs, preservatives or latex, so they're all appropriate for individuals with those allergies.