aidarrowcaretcheckclipboardcommenterrorexperienceeyegooglegownmicroscopenavigatepillTimer IconSearchshare-emailFacebookLinkedInTwitterx

Your COVID Vaccine Questions, Answered

Last updated: April 13, 2021

The COVID-19 vaccine rollout is the largest mass-immunization effort in US history — and there’s a lot to keep track of. Between finding your place in line and knowing which vaccines are available, getting a handle on the relevant info can be overwhelming. So let’s start with the Big Questions. Here’s a breakdown of what you need to know about the COVID vaccine, and then some.

When can I get a COVID vaccine?

In the past month, eligibility has expanded significantly across the country. Earlier this month, President Biden encouraged all states to open up vaccine appointments to everyone 16 and older by April 19. Most states have already hit this goal.  

That means now is the time to book an appointment for a shot if you haven’t already.

How do I make an appointment for my shot?

Each state is in charge of its own COVID vaccine distribution plan. There’s no single, centralized hub for where all Americans can book vaccine appointments. Some state health department sites have tools to help you find nearby vaccination sites and schedule appointments — find yours via the CDC’s Vaccines for COVID-19 webpage. The CDC page also links to, which has up-to-date information on vaccine availability by zip code and links to online schedulers on pharmacy and clinic websites. Expect these online schedulers to get busy; you may need to revisit them frequently to claim a time, especially as eligibility is expanded to all adults.

When checking appointment sites for availability, be sure to have pertinent health information handy. After you see an opening, you might only have a few minutes (or less) to book. Be patient and persistent, and pay attention to local news for announcements about new locations offering shots.

A few useful websites for finding and booking appointments

How are the vaccines administered?

To be maximally effective, the Pfizer vaccine requires two injections into the muscle, administered three weeks apart. The Moderna vaccine also requires two shots, but they’re administered four weeks apart.

The Janssen vaccine from Johnson & Johnson only requires one dose.

Is one vaccine better than another? Should I hold out for the Pfizer or Moderna vaccine, rather than get the Johnson & Johnson?

On April 13, the CDC recommended a pause on the use of the Johnson & Johnson (J&J) vaccine after the emergence of blood clotting disorders in six recipients. So far, more than 7 million people in the US have received the J&J shot. The pause is expected to last only “a matter of days,” according to Dr. Janet Woodcock, the acting commissioner of the FDA, and will determine if the vaccine caused the blood clots.

When the J&J is available again, consider any of the vaccines’ potential risks in the context of their benefits:

  • The Pfizer and Modern vaccines are both about 95 percent effective at preventing COVID illness after two doses.
  • In US trials, the Johnson & Johnson vaccine was shown to be about 72 percent effective against moderate COVID infections and 86 percent effective against severe infections.

Differences aside, experts say the best vaccine to get is the one offered to you.

If you can get it, any one of these three vaccines would be great,” says Dr. Ed Septimus, an infectious disease specialist and professor of medicine at Texas A&M. “All of them will provide the protection we need, and the sooner we get all people vaccinated, the better. The sooner we stamp down [virus] activity in our community, the less opportunity there is for variants to emerge.”

Specific to J&J, it’s important to recognize how effective it really is against COVID.

“A lot of people are losing sight of the fact that all we were hoping for was at least 50 percent efficacy for a vaccine,” says Katelyn Jetelina, an assistant professor at UTHealth School of Public Health in Dallas. “J&J is already outperforming what we were shooting for.”

The most significant finding from the J&J trial is the vaccine’s 100 percent effectiveness against COVID-related hospitalizations and deaths. “That’s what is most important to pay attention to — the rate at which people are in the hospital and die,” Jetelina says, “and J&J is extremely effective [by this measure], just like Moderna and Pfizer are.”

Also, vaccine efficacy is not an apples-to-apples comparison; clinical trials for the three vaccines had some differences. For one thing, Pfizer and Moderna both tested for symptomatic COVID infections (although not in the same ways), while J&J assessed protection against moderate-to-severe COVID illness. Also, the Pfizer and Moderna clinical trials ended before researchers detected newer coronavirus variants.

As Dr. Nirav Shah, director of the Maine CDC, said in a press briefing, “It’s not vaccine against vaccine – it’s vaccine against virus.”

The J&J vaccine has some advantages. Most obviously, “it’s a single-dose vaccine, so you don’t need to scramble for a second dose,” says Seattle-based Dr. Chunbai Zhang, medical director of VA Puget Sound Health Care System. It can also be stored at room temperature, potentially making distribution easier. And, based on clinical data, the J&J shot appears to have milder side effects than the other two vaccines.

Collectively, we’ll fare better if more people get vaccinated with a range of excellent to great vaccines vs. fewer people getting only the most effective vaccines.

Do I really need a second shot of the Pfizer or Moderna vaccine?

Both the Pfizer and Moderna vaccines require two shots to work the way they’re supposed to. Based on clinical trial results, the Pfizer vaccine was estimated to be 52.4 percent effective at preventing COVID illness after one dose, and 95 percent effective after two. The results were similar for Moderna. A recent UK study found that one dose of the Pfizer vaccine reduced the risk of infection by 72 percent after three weeks — good news about the effectiveness of the vaccines, but not conclusive as to the necessity, or lack thereof, of the second dose.

Whenever possible, the second dose should be administered 21 or 28 days after the first dose (for Pfizer and Moderna respectively). But the CDC permits waiting up to six weeks (42 days) between doses in situations where it’s not feasible to adhere to the recommended schedule. Still, skipping the second shot altogether, for any vaccine with a two-dose regimen, isn’t wise. In fact, the government is paying vaccination providers more money to administer second doses as an incentive to make sure patients come back.

Once you get both doses, it takes one to two weeks for the vaccine to become maximally effective against COVID.

Why does the Johnson & Johnson vaccine only require one shot?

The Johnson & Johnson (J&J) single-dose vaccine uses an adenovirus, the type of virus that causes the common cold, as a messenger to deliver instructions to the body’s cells. That differs from the Pfizer and Moderna vaccines, which use messenger RNA (mRNA) technology to deliver genetic material to cells with instructions for making a non-infectious piece of the coronavirus’s spike protein.

By design, the J&J vaccine is a single dose — though the company is researching the efficacy and safety of a second dose, which would be administered eight weeks after the first. Results are expected in May.

“The big question,” Jetelina says, is “what do we do if we see that two doses are more effective?” If Johnson & Johnson’s trials of the two-dose vaccination produce a significant increase in effectiveness — to something closer to 95 percent — you should expect to hear news of the availability of second shots for those who already received the initial J&J vaccine.

Is the vaccine actually free?

The vaccine is supposed to be free for everyone in the US, no matter where you get vaccinated or what type of insurance you have (or don’t have). (Your taxpayer dollars are paying for vaccine doses.) While it seems likely that COVID vaccination will remain free through at least the end of the calendar year, the federal government hasn’t said so explicitly. 

If you have insurance, you’ll be asked for your insurance information — but you should not incur any out-of-pocket costs. If you don’t have insurance, you’ll still be able to get the vaccine free of charge.

Now for the fine print: Some vaccine providers may charge an administrative fee for giving the shot, but patients are not responsible for paying it. Instead, providers are supposed to bill private insurance plans (most of which cover the full cost of vaccination) or the government (via the CARES Act Provider Relief Fund).

When booking your vaccine appointment , don’t hesitate to contact the vaccine provider directly to ask about charges. Be straightforward if you have any cost concerns; money should not be a barrier to getting your shots.

If you think you’ve been charged for COVID vaccination incorrectly, reach out to your local public health department.

Will the vaccines work against new COVID variants?

Currently available COVID vaccines do recognize, and thus confer some degree of protection against, newer strains of the coronavirus, such as those found in the UK and South Africa, according to the director of the CDC. Though experts don’t know just how effective the vaccines are against these more recent, highly contagious variants, they do agree they’re the best defense against them. “The vaccines should be effective against variants because the variants are similar to the initial strain,” Zhang says. “The mutations share enough of their composition with the initial strain for a vaccinated immune system to recognize them.”

Vaccines currently in development — including boosters from Pfizer and Moderna — are being tested against newer strains of COVID, but your best bet for limiting your risk for a serious infection is still the vaccine available to you.

Note, too, that there isn’t any evidence that the vaccinations themselves are spurring the mutation of COVID and creating new variants. The virus — including mutant strains — spreads through the population faster when fewer people are vaccinated, so the more of us who get our vaccine shots, the better chance we have against all strains. 

These vaccines were developed so quickly. How do we know they’re safe?

After nearly 22 million Americans had been vaccinated with the Pfizer and Moderna vaccines, the CDC reported that the shots are as safe as the trials indicated.

Clinical testing for the vaccines, though expedited, has been rigorous; any approved vaccine has been tested on tens of thousands of volunteers. The FDA requires vaccine manufacturers to provide two months of safety data in their applications for emergency use. That’s true for currently available vaccines and any additional ones the FDA OKs for emergency use.  

The April 13 pause on the use of the Johnson & Johnson vaccine is intended to allow the CDC and FDA to examine possible links between the vaccine and a blood clotting disorder that emerged in six recipients. They will also determine whether to continue to authorize use of the vaccine for all adults or modify the authorization, possibly limiting it to certain population groups.

What should I know about side effects?

Recently, six recipients of the J&J vaccine developed serious blood clotting disorders, resulting in one death and a pause of the use of the vaccine while the CDC and FDA examine a possible correlation. The risk of developing dangerous blood clots for people who have received the J&J vaccine is very low, according to the CDC, but you should seek medical treatment if you develop severe headaches, abdominal pain, leg pain, or shortness of breath.

For the vast majority of people, the most important thing to know is that it’s impossible to get COVID from vaccination because, among other things, the vaccines don’t contain any live virus. But you might experience mild side effects from your shot(s).

Vaccine trials for Pfizer, Moderna, and J&J found that mild-to-moderate side effects are relatively common; for Pfizer and Moderna, side effects are more likely to develop after the second shot. J&J’s side effects are reportedly less likely and, when occurring, milder than those of Pfizer’s and Moderna’s vaccines. More recently, recipients of the J&J shot in several states reported side effects including dizziness, nausea, and fainting, though these symptoms are still very rare.

Anecdotal reports from people who’ve been vaccinated with Pfizer or Moderna support the study findings. Side effects tend to last one or two days and resemble symptoms of COVID itself, in addition to typical vaccine side effects: Pain, swelling, and redness at the injection site; whole arm soreness; fatigue; headaches; muscle and joint pain; fever; chills. While these post-shot symptoms might be unpleasant and unnerving, they aren’t dangerous. In fact, they’re a sign that your immune system is responding to the vaccine the way it’s supposed to. (Not having side effects is normal too.)

There is data indicating that women are more likely than men to experience worse side effects from the vaccines, possibly due to several factors. Doctors have also reported delayed skin reactions to the Moderna vaccine — arms turning red, sore, itchy, and swollen a week or so after the shot. These reactions appear to be harmless.

Keep in mind, too, that you should be required to wait for at least 15 minutes after a vaccination shot before leaving the administration site. This is to make sure you don’t have any serious side effects, including an allergic reaction (see “Should I be concerned about the possibility of an allergic reaction?” below).

Data on side effects is being tracked closely as vaccinations continue to roll out. Once you get vaccinated, you can report your own side effects, however mild, using the CDC’s V-safe app. The app will also send you a reminder when it’s time to get your second dose.

In the US, according to the CDC, no severe side effects, aka “adverse events,” have been reported as a result of COVID vaccines. An adverse event means a long-term or serious illness, hospitalization or death caused by vaccination. As more and more people get vaccinated, the possibility of an adverse event occurring increases — but the likelihood of any one person experiencing one is very, very low.

That said, if you do have an adverse event, you should talk to a healthcare provider and report it through the Vaccine Adverse Event Reporting System.

Can I take pain relievers for the potential side effects?

You may have heard from friends or relatives who have received their second Pfizer or Moderna shots that they did, indeed, experience some uncomfortable side effects — particularly pain and soreness in the arm where the shot was administered. Though taking ibuprofen or acetaminophen (Tylenol) if and when you feel significant discomfort after your shot is OK, the CDC recommends against taking anything before your shot, as these medications’ impact on the vaccine’s efficacy is unknown. 

“You want to maximize your immune system’s chance to develop a counter-attack to COVID with the vaccination,”  Zhang says. “Your body’s immune system should be fully awake when you’re getting vaccinated. You don’t want to numb it with a pill just before provoking it to get a response.”

Should I be concerned about the possibility of an allergic reaction?

In a very small number of cases, each of the three vaccines has triggered anaphylaxis, a severe, life-threatening allergic reaction. (The CDC reported 16 incidents caused by the Moderna vaccine and 46 due to the Pfizer vaccine out of a combined 13.7 million doses administered before January 13; 2 recipients of the J&J vaccine had allergic reactions during the trials.) Accordingly, the CDC reiterated that vaccine administrators should observe anyone with a history of anaphylaxis for 30 minutes afterward and have epinephrine (EpiPens) on hand in case of an allergic reaction.

Who shouldn’t get vaccinated?

At this point, the only group expressly excluded from the CDC’s “OK to vaccinate” recommendation is kids 16 and younger.

While initial COVID vaccine trials did not include pregnant women and immunocompromised people, there is now some data supporting the vaccines’ safety and efficacy for these groups. A study published in The American Journal of Obstetrics and Gynecology, for instance, shows that the vaccines are safe and effective for pregnant and breastfeeding women and may even offer some protection for their babies.

Studies with children are also underway. According to Fauci, vaccines for kids as young as first graders could be authorized by September.

Do I need to get the vaccine if I’ve already had COVID?

Pierre says you should get the vaccine even if you’ve had COVID previously. While you most likely developed antibodies, experts don’t know how effective those antibodies are against COVID, or how long they last. What they do know is that getting vaccinated confers stronger and longer-lasting protection against COVID than getting sick with COVID does.

For people who’ve had COVID, recent studies show that even one dose of either the Pfizer or Moderna vaccine greatly amplifies the amount of antibodies in the blood, conferring protection against multiple coronavirus variants. While this research points to the possibility that one dose of the Pfizer or Moderna vaccine might be enough for those who’ve had COVID, the CDC still recommends a two-dose regimen for everyone.

If you’ve had COVID and were treated with monoclonal antibodies or convalescent plasma, wait 90 days after the initial onset of symptoms to begin vaccination.

Is it possible to get the COVID vaccine and still get COVID?

COVID immunization makes getting severe COVID very unlikely, but not impossible. (For comparison’s sake, both the Pfizer and Moderna vaccines are 95 percent effective in preventing severe COVID illness, whereas a seasonal flu shot is about 40 percent effective on average — and definitely worth getting every year.) There is growing evidence the vaccines do prevent infection as well as disease, but this has yet to be definitively proven. That means there’s still a possibility that someone who’s been vaccinated could still be a silent carrier and unknowingly infect others.

What we don’t know yet is how well COVID vaccination protects people against asymptomatic infections. While experts believe that the COVID vaccines — like most vaccines — should reduce asymptomatic disease, this has yet to be proven. That means we also don’t know if someone who’s been vaccinated can still become a silent carrier and unknowingly infect others.

“The important message here is that even if you’ve been vaccinated, that’s just a protection for you against severe disease,” Pierre says. “You need to continue to wear your mask and physically distance because you could still be at risk yourself and put others at risk.”

As a positive sign that the vaccines are helping to limit the spread of COVID, the CDC has updated its recommendations for what to do following exposure to an infected person, stating that those who have been fully vaccinated do not need to quarantine.

Will COVID vaccination become mandatory?

The government is unlikely to mandate universal COVID-19 vaccination, though this could change as we learn more about the disease and the vaccines — and how they affect us over time.

But unvaccinated people could encounter a range of restrictions. For example, airlines could require proof of vaccination for booking or boarding flights. And employers have the right to make vaccination a condition of employment, and to fire workers who don’t comply. The only exception, Winslow says, is for those with medical exemptions, says Dr. Dean Winslow, an infectious disease physician at Stanford Healthcare in California. In that case, an employer would have to make a “reasonable accommodation,” such as having that person work remotely, so they could continue to do their job.

Keep in mind, the goal of this rollout is to vaccinate enough people to achieve herd immunity so we can control the spread of the virus. The percentage of a community that needs to be vaccinated to reach herd immunity is different for every virus. For the coronavirus, Winslow says, the magic number is thought to be about 70 percent. But that’s an educated guess; some experts have put it higher. 

In order to return to something like our pre-pandemic lives in the near future, we need to get vaccines into the arms of the vast majority of eligible people.

Can I spend time with older family members or others who’ve been vaccinated even if I haven’t been yet?

If an older relative is vaccinated and eagerly expecting your visit, that’s great — but don’t let the prospect of a happy reunion lower your guard altogether. Before making travel plans, make sure they’ve been vaccinated for at least two weeks before you see them, says Dr. Chad Sanborn, a pediatric infectious disease specialist at KIDZ Medical Services in West Palm Beach, Florida. He also advises continuing to wear your mask while you’re with them. It’s a good idea for them to ask their doctor about it, too, if that’s feasible. 

In clinical trials, the Pfizer vaccine showed similar protection in the over-65 and over-75 groups as it did in younger adults. While those results are promising, Sanborn urges caution, particularly if older family members have suppressed immune systems. It’s possible the vaccine won’t be as effective for them. Time and data will tell.

In general, Sanborn believes we need to see increased vaccination coverage and decreased COVID infection rates before we start freely gathering with people like it’s 2019. “We are still learning the kind of protection the vaccine offers in real life.”

Can I stop wearing a mask once I’m vaccinated? What about when I’m with other people who have been vaccinated?

For now, everyone needs to continue wearing masks and maintaining social distance in public — whether or not they’re vaccinated. 

For those who have been fully vaccinated, the CDC recommends avoiding medium- and large-sized gatherings, but does allow for small gatherings without the need for masks — either with other fully vaccinated people or with unvaccinated people from one other household, unless anyone from that household is at increased risk for severe COVID illness. And if you do come in contact with someone who has COVID, you do not need to quarantine or get tested (unless you live in a group setting). 

However you choose to socialize post-vaccine, be considerate of those not yet eligible for their shots — and who could still get sick. 

“You have less of a chance of getting sick after getting vaccinated,” says Sanborn. “But without masks or social distancing, you may actually have a higher chance of acquiring an asymptomatic infection and giving it to others who can’t receive [the vaccine], or haven’t been vaccinated yet.”

For those who are still waiting to get their shots, the loosening restrictions for vaccinated individuals may compound feelings of impatience, but they’re a sign of hope. “It means we’re getting closer to getting vaccinated,” says Melissa Hawkins, an epidemiologist and Director of the Public Health Scholars Program at American University. “We all need to still wear masks in public places and keep up the always-good practice of frequent handwashing. It’s all about harm reduction. So yes, it’s OK for vaccinated folks to get together and hang out with low-risk unvaccinated people. But I have four kids and will continue to be mindful of my behavior even when my husband and I are vaccinated.”

What happens if my state runs out of the vaccine I received before my second dose of Pfizer or Moderna? Will I only get one? Can I get a second dose of a different vaccine?

It is very unlikely you won’t be able to get your second Pfizer or Moderna vaccine dose because of a shortage. The plans for the phased vaccine rollout account for the importance of second doses being available to everyone who needs them. High demand and distribution bottlenecks could mean your second dose is postponed. But delaying the second shot by as much as two weeks won’t affect the vaccine’s efficacy, according to Dr. Anthony Fauci, the president’s special adviser for the coronavirus.  

While health officials have emphasized that Pfizer and Moderna vaccines are not interchangeable with each other, the CDC has also said that patients can mix vaccines in “exceptional situations.” What constitutes an “exceptional situation”? If, for some reason, there’s no documentation of which vaccine you received the first time, you can get a second dose of whichever is available. Or if it’s time for your second dose and there’s no feasible way to get the vaccine you received within the next three to four weeks, you’d get the other one. “That would be the rare case of someone who cannot travel and there is no supply for the same dose for a while,” says Zhang. “It is far more likely and acceptable to wait than to mix vaccines.”

To better your chances of getting matching vaccine shots, schedule your appointment for your second shot before or immediately following your first shot. Some sites allow you to do this during your 15-minute post-shot waiting period. Also, be sure to hang on to your vaccine card — snap a pic with your phone, too, just in case. And if, for some very unusual reason, you can’t get your shot on your appointed day, don’t sweat it: a few days either way isn’t going to impact the vaccine’s efficacy.

Do I need to save my vaccine card? Will I need to show proof of vaccination to work or travel?

When you get your first COVID-19 dose, you’ll get a vaccine card. It states which vaccine you receive, as well as the date and vaccination site location. The primary purpose of the card is to help make sure you return for your second dose on schedule. “It’s a good idea to hold on to the cards for documentation of vaccine status,” Hawkins says. “Though, it’s not a good idea to post it on social media.”

While it’s important to hold onto your vaccination card, it’s unlikely you’ll need it as proof of vaccination for work or travel. Some airlines are introducing digital health passes to ensure that passengers are COVID-free (based on negative test results) and, eventually, vaccinated against the coronavirus, but you won’t have to flash your paper card to board a flight. “The card you get after the shot won’t be used as a passport,” Zhang says. “I expect another form of proof will come from the CDC or another government agency.”

Ready to book a doctor’s appointment? Visit Zocdoc.

Show Comments (5)
  1. jim low


  2. Sandi

    I received an article forwarded to me about the vaccines. The article said it is possible to get bell palsy from the vaccine and never recover. please let me know about this.


    I got my first vaccine but no one has scheduled my second vaccine. They said this site would notify me but I have not got a notification.

  4. Robin Secrist for Gerald Secrist

    I accedently, canceled my husbands second vaccine, we live in Chicago, he was vaccinated at the event center, how can I reschedule?

    1. Elizabeth Sims

      I did the same, accidently cancelled my second appt thinking I could reschedule because I was scheduled to be out of town when second shot was due. How do I reschedule?

Leave a Comment

About us

The Paper Gown, a Zocdoc-powered blog, strives to tell stories that help patients feel informed, empowered and understood. Views and opinions expressed on The Paper Gown do not necessarily reflect those of Zocdoc, Inc. Learn more.