How does the vaccine work?


Do I have to wear a mask once I'm vaccinated? Do I need to get tested weekly still?

  • Yes. Researchers do not have enough information yet to say if or when people can stop wearing masks and avoid close contact with others.
  • Once you are vaccinated, you can still get the virus, but you will have mild to no symptoms. However, there is still as risk that you could transmit the virus to someone who has not been vaccinated and they could get very sick.
  • Once the majority of people are vaccinated, life will be able to return to more normal conditions as determined by health and government authorities.

When will I be eligible for the vaccine?

Please refer to the Commonwealth of Massachusetts website for information on when you will become eligible for the vaccine. For Connecticut residents, please visit the Connecticut State website for more information.

Learn more about vaccine equity and hesitancy through some of these resources:

What are the side effects to the vaccine?

  • Common side effects include pain and swelling at the vaccine site, fever, chills, tiredness, and headaches.
  • These side effects can affect your ability to do daily activities but should go away within a few days.
  • You can take ibuprofen or acetaminophen for any pain and discomfort you may have.
  • These side effects are normal signs that your body is building protection!

About the Janssen/Johnson & Johnson vaccine:

The FDA and CDC have recommended a pause on the use of Janssen / Johnson & Johnson vaccine because they've seen a "safety signal". 

The safety signal is 6 cases of a rare combination of a blood clot called cerebral venous sinus thrombosis (CVST) and thrombocytopenia. CVST is clotting that occurs in the brain's venous sinus, which prevents blood from draining out of the brain, therefore causing a stroke. Thrombocytopenia is low platelet count.  Clots are usually treated / prevented with heparin, an anticoagulant. This is particularly true among hospitalized COVID patients.

However, this rare combination of CVST and thrombocytopenia seems to be causing a rare situation in which the body produces antibodies to a protein called platelet factor 4 (PF4). This antibody is also present in a condition heparin induced thrombocytopenia (HIT). If a patient has these antibodies to PF4, we actually can't give them heparin - heparin will make the clotting worse. So it requires a different treatment from the one normally used - the normal treatment will make it worse. That's key information. So there's a rare side effect (clot), and then the rare side effect requires a rare treatment (not heparin).

The 6 cases have been in women under 50 within 2-3 weeks of receiving the vaccine. One is in critical condition. One has died. A causal link has not been established, but there is enough similarity between the cases and the outcome is rare enough that it caused an alert (the "safety signal") so they can investigate further.

There are many posts going around comparing risks of different kinds of blood clots - this is a very specific type of clot, so broad comparisons aren't super helpful in understanding risk comparison of this specific type of clot (middle picture). Scientists are getting data on the specific type of clot to make a better comparison, but you can see that the risk is increased compared to the general population (last picture). One thing that's helpful about the risk comparison posts, however, is that they highlight that there's risk in everything. The overall risk of a blood clot if you have received the JJJ vaccine is extremely low - lower than other risks we readily accept. In other words, if you've received the JJJ vaccine, don't panic.

How does herd immunity work?


How does the vaccine affect fertility, pregnancy, and breastfeeding?

  • If you are pregnant, you should speak with your healthcare provider to discuss your options for vaccination.
  • If you are breastfeeding, you may choose to be vaccinated especially if you are in a high-risk category. There is no evidence that mRNA vaccines are excreted through breast milk but you should speak with your healthcare provider for more information.
  • What if you want to get pregnant someday? Experts believe that the COVID-19 vaccines are unlikely to pose a risk to a person trying to become pregnant in the short or long term.

Do the News SARS-CoV-2 Variants Affect Vaccine Efficacy?

So far, the new variants seem to increase the ability of COVID-19 to spread but do not influence how sick someone gets from the disease. The current vaccines appear to work against the new variants. When vaccines are created, they are designed to create many different antibodies to differing parts of the virus so that even if one part of the virus mutates, the antibodies may recognize another part of the virus. It is possible that there will be a variant that reduces vaccine efficacy, and the companies that make vaccines are creating new ones that should work against new strains of SARS-CoV-2. (Journal of the American Medical Association)

Resources from the Center for Disease Control

What's the difference between the vaccines? Is one better than the other? What else should I know about the vaccines?

Key Things to Know About Vaccines

Why should I get the vaccine?

Benefits of Getting a COVID-19 Vaccine

If I had COVID-19, should I still get the vaccine, and other commonly asked questions:

CDC Vaccine FAQ

Other Resources

THE CONVERSATION: Between Us, About Us kicks off with an open and honest conversation between W. Kamau Bell and Black doctors, nurses and researchers that gets to the heart of Black people’s questions about the COVID-19 vaccines. This new campaign from KFF’s Greater Than COVID and the Black Coalition Against COVID launches with 50 FAQs designed to dispel misinformation and provide accessible facts about the vaccines from Black health care workers. View their video below: