Differences Among the Three Covid Vaccines (cdc.gov):
This is an mRNA two dose series given 28 days apart to anyone 18 years of age and older. Side-effects usually come about within a day or two of receiving the vaccine. After two doses, the vaccine was 94.1% effective among diverse groups of people, but can be slightly lower among those older than 65 years old. Storage can be in the fridge or freezer, but there is a tighter range of temperature in the freezer and it must be adjusted accordingly. Each dose contains 100 micrograms.
This is an mRNA two dose series given 21 days apart to anyone 16 years of age and older. In clinical trials, most side-effects were against the second dose of the vaccine, and the symptoms were rated as mild to moderate. Storage should be in a -80 degree freezer and it is a multidose vial. After two doses, the vaccine was 95% effective among diverse groups of people. Each dose contains 30 micrograms.
Johnson and Johnson:
This is a viral vector one dose series given to anyone 16 years of age and older. Most side-effects were mild or moderate after given the vaccine within seven days of injection. Side-effects were more common among the ages of 18-59 as compared to ages 60 and older. It has a 63 percent efficacy rate, but is a strong preventative for strong coronavirus reactions. In clinical trials, no one was hospitalized within four weeks of receiving the vaccine for coronavirus. Early evidence also shows that this may prevent asymptomatic infections, but more data is required. Storage should be in a fridge and not in the freezer.
The vaccine itself does not contain eggs, preservatives, or latex. It's recommended that those who have allergies to ingredients in the COVID vaccines, such as polyethylene glycol in the mRNA vaccines or polysorbate in the viral vector vaccine, or have gotten immediate (within four hours) allergic reactions should not get their first or second dose, respectively. Common side effects are: swelling, redness, nausea, fatigue, headaches, myalgia, fever.