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So you got your COVID vaccine—here's what you can safely do

August 20, 2021

So far, more than 4.4 million people have been fully vaccinated against COVID-19 in Massachusetts.

As more of the public gets the COVID-19 vaccine, what will change? Will we still need to take the precautions we take now, like wearing masks and social distancing? And is there an end in sight, given the spreading Delta variant?

Dr. Armando Paez, chief of Infectious Diseases at Baystate Medical Center, helps clear up some confusion about what getting vaccinated means for our community life.

What is considered fully vaccinated?

According to the Centers for Disease Control, you’re considered fully vaccinated:

  • Two weeks after your second dose in a 2-dose series, such as the Pfizer or Moderna vaccines, or
  • Two weeks after a single-dose vaccine, such as Johnson & Johnson’s vaccine (currently on hold until further notice)

Can I get COVID-19 after being fully vaccinated?

After you get vaccinated, it takes your body approximately 14 days from the last recommended dose of a series to build up immunity against COVID-19. In the meantime, you could still be infected if you don’t take appropriate precautions. Even after the 14 days, there is a small chance that you could get COVID-19 and pass the infection on to others, although this is less likely.

The vaccines have been shown to protect immunized people from serious illness and death, but that doesn’t mean we’re completely invincible after getting the shot.

How effective are the vaccines?

The CDC studied the effectiveness of the vaccines available, and real world data on vaccine effectiveness have also been reported.

After the second dose of the Pfizer or Moderna vaccines, researchers found them to be at least 90% effective and immunity from vaccination is expected to last for at least six months. A third booster shot is probably needed within a year after the 2-dose series according to the vaccine top executives.

In a Food & Drug Administration (FDA) briefing, the Johnson & Johnson vaccine (currently on hold) was deemed 74% effective against COVID-19 infections that do not show symptoms.

Dr. Paez says that circulating variants can affect vaccine effectiveness. Fortunately, the vaccines are effective so far against variants – but the Delta variant is more infectious.

“What is important is the ‘herd immunity,’ which is the critical level of immune individuals that will end the pandemic by natural infection and vaccination,” Dr. Paez said.

He says that researchers previously estimated 60-70% of the population have to be immune either by natural infection or vaccination to achieve herd immunity. But he says that with the circulating variants a higher threshold will be needed to achieve this.

For perspective, the World Health Organization has herd immunity levels for polio at 80%. It puts herd immunity for measles at 95%.

Possible Need for Booster

We’re still learning about how long vaccines can protect people.

So far, research shows mRNA COVID-19 vaccines (that’s Pfizer and Moderna) can protect you for at least six months. Vaccinated people could have immunity for even longer than that, but it hasn’t been fully studied yet.

Some vaccines are a “one and done” deal. Other vaccines like the tetanus shot require boosters. Scientists still don’t know whether you’ll need regular shots, months or years after your initial ones.

The CDC recommends a booster shot for severely immunocompromised people at least 28 days after a second dose of Pfizer or Moderna. 

The “silent spreader”

Scientists are also still learning what effect vaccines will have on the spread of COVID-19.

Preliminary data from Israel suggest that those who received Pfizer-BioNTech COVID-19 vaccine and later developed COVID-19 have a four-fold lower viral load (key driver of transmissibility) than unvaccinated people. This supports the notion that vaccination can decrease virus transmission.

Some worry that while getting the vaccine may protect you from the virus, it could make you a “silent spreader” – unknowingly giving COVID-19 to unvaccinated family, friends, and strangers.

Dr. Paez explains “silent spreaders” are asymptomatic (don’t have COVID-19 symptoms).

“The virus is present in the nose and respiratory tract, but the person does not get sick – either because of their own immune system or because they’ve been vaccinated,” Dr. Paez says.

However, the virus can still transmit this to someone who doesn’t have those same immune system protections.

So when you get vaccinated, it’s important to know what you can safely do without harming others.

Once I’m fully vaccinated…

Do I have to follow social distancing guidelines?

The CDC now says you don't have to stay six feet apart from people unless it's required by federal, state, or local laws.

Some businesses and workplaces may still require you to social distance.

Do I have to wear a mask?

It depends. The CDC does say you should consider wearing a mask in crowded indoor spaces in areas with high numbers of COVID-19 cases or in cases where you will be in close contact with others who are not fully vaccinated.

According to the CDC, if you are fully vaccinated, you do not have to wear a mask indoors or outdoors unless:

  • It's required by federal, state, or local laws
  • It's required by a business, like a grocery store or a bank
  • Your workplace requires wearing masks
  • You are traveling on planes, buses, trains, and other forms of public transportation
  • You are visiting a healthcare location or nursing home
  • You are a patient in a healthcare setting
  • You are visiting a more crowded living area like a homeless shelter or a prison

Some scientists have disagreed with some of this guidance, urging caution for people who are fully vaccinated.

If you are immunocompromised and vaccinated, you will want to keep wearing a mask as you may still be vulnerable to COVID-19.

You may also consider continuing to wear a mask if:

  • You are in a crowded indoor location where others may not be wearing a mask
  • Your community has a low vaccination rate and you suspect unvaccinated people may be in public without masks
  • You work in a service industry job and do not know the vaccination status of your customers
  • You live with unvaccinated or immunocompromised people

The CDC says there are still a lot of unknowns about vaccine protections, including:

  • Whether the vaccine can stop you from being a "silent spreader" to the unvaccinated and immunocompromised
  • How long immunity from vaccines last
  • Whether vaccines can fully protect against COVID-19 variants
  • The number of people needed to be vaccinated in order for us to have "herd immunity"

Mixed Vaccinated/Unvaccinated Households

If your household has some vaccinated people and some who are not vaccinated, you'll want to take precautions.

The CDC advises parents make sure their children under 12 years old wear a mask when in public. You can set an example by wearing one yourself.

If you have children under 2 years old, which cannot be vaccinated or safety wear a mask, limit visits with unvaccinated people and keep safe distance away from strangers in public. The risk for getting a severe case of COVID-19 is lower for young children, but they could still get the disease.

Some adults in your household may not be vaccinated. They will still need to follow CDC safety guidelines for the unvaccinated, including social distancing and wearing a mask.

Do I need to quarantine if I am exposed to someone with COVID-19?

It depends on your living situation.

You don’t need to quarantine unless you have symptoms.

But the CDC says if you live in a more crowded setting like a group home or a detention center, you should quarantine for 14 days after being exposed to someone with COVID-19. You should get tested even if you don’t have symptoms.

Can I travel again?

Delay travel until you're fully vaccinated. People who are fully vaccinated with an FDA-authorized vaccine or a vaccine authorized for emergency use by the World Health Organization can travel safely within the United States.

If you travel internationally, you do not need a COVID-19 test unless your destination requires it.

If you are coming back to the United States, you need to get a negative COVID-19 test before catching a flight. You’ll also need to get tested again 3-5 days, but you won’t have to self-quarantine.

Make sure to research what rules your destination country may have in place, so you can be in compliance there, too. 

Learn more about traveling safely.

Can I go to large gatherings?

The CDC recommends avoiding large gatherings.

Phase 4 of Massachusetts reopening plan puts some limits on gatherings.

For event venues and public places:

  • 100 people indoors
  • 150 people outdoors

For private house and backyard gatherings:

  • 10 people indoors
  • 25 people outdoors

Am I exempt from COVID-19 rules set by my employer?

Follow safety guidelines set by your employer. As Massachusetts businesses reopen, they’ll have to follow new workplace safety guidelines set by the state.

Healthcare workers still need to wear a mask while at work.

Learn more about the COVID-19 vaccine

If you are an eligible Massachusetts resident, schedule a vaccine through If you are a Connecticut resident, visit

Find out the differences between the three available vaccines.

Learn what to expect when you get vaccinated.

Get Your COVID Shot

CDC recommends everyone ages 5 and older get a COVID-19 vaccine to help protect against COVID-19.

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