Q&A From Webinar

Updated 2/9/2021

This is a compilation of questions submitted prior to and during the February 5, 2021 webinar, COVID-19 Vaccine: What You Need to Know.   

Responses from Dr. Amanda Westlake, Infectious Disease Specialist and Primary Care Provider at Baystate Mason Square Neighborhood Health Center and Dr. Paul Pirraglia, Chief of General Medicine and Community Health at Baystate Health.



  • I have a peanut allergy. Can I take vaccine?
    • Yes. Food allergies are NOT a reason not to get COVID vaccine.  There is no cross-reaction with ingredients in the vaccine. ​​​​​​
  • Can someone arrange to get vaccine in a medical center if risk of allergy?
    • ​​​​​​​Yes. 

  • What are the vaccine ingredients?
    • ​​​​​​​​​​​​​​Unlike other vaccines, there are NO preservatives in the current mRNA (Pfizer and Moderna vaccines).  The main ingredient that is of concern from an allergy standpoint is polyethylene glycol (the active ingredient in Miralax – a laxative – and in bowel preparations for colonoscopy). 

Vaccine & Safety

  • The vaccine was created so quickly, is it really safe to take it? How do we know?
    • ​​​​​​​​​​​​​​​​​​​​Yes.  The vaccine was created rapidly because all scientists in the world were working simultaneously to respond to this global health crisis.  No shortcuts were taken in the clinical trials that included ~40,000 participants that showed the vaccines are both safe and have efficacy >95%.  They were able to be brought to the public so soon after clinical trials because the federal government funded manufacturing. ​​​​​​​
  • How large are the clinical trials - 100 people, 1000 people, 5000 people???  Please define large.  I believe in vaccinations.  I can't wait to get mine.  But worried people need to hear a real number not just the word "large".
    • For Pfizer: 21,720 people received vaccine & 21,728  people received placebo.  For Moderna: 15,181 people received vaccine & 15,170 received the placebo​​​​​​​

  • What is the difference between the Pfizer and Moderna vaccines? Is one safer or more effective than the other?

    • ​​​​​​​​​​​​​​​​​​​​​​​​​​​​They are equivalent from a safety and efficacy standpoint.  The only difference from an operations standpoint is that the Pfizer doses are administered 3 weeks apart, whereas Moderna are 4 weeks apart. ​​​​​​​

  • Once the first dose of the vaccine is taken, how protected is someone from contracting Covid-19? What will happen if someone only takes the first dosage of the vaccine and does not take the second dosage? Will they no longer be protected?

    • ​​​​​​​​​​​​​​​​​​​​​​​​​​​​Partial protection from the first dose begins at ~12 days after first dose.  By the time of the 2nd dose, people have >80% protection, and by 2 weeks after the second dose there is >95% protection.

    • ​​​​​​​The first dose confers the majority of the protection.  The second dose is a booster that increases the level of protection and increases the duration of protection.  This is the reason that some public health experts are recommending delaying the second dose for up to 3 mos in order to get the first dose to the greatest number of people in the shortest period of time. 

  • Once both dosages of the vaccine have been taken, how protected are people and how long does the protection last? ​​​​​​​

    • Beginning 14 days after the 2nd dose protection is >95%

    • The duration of protection – based on natural infection or vaccine – is not yet definitively known, mostly because the virus has only been circulating for a year.  Best available evidence points to a duration of protection for at least 6-9 mos.

  • After being fully vaccinated (taking both dosages) will another booster be necessary later down the road?

    • Unclear at this point.  If variants (ie, versions of the virus that contain mutations) such as the South Africa, UK and Brazil variants a) become widespread in the US and b) result in lower vaccine efficacy, it is possible that we will need a booster to “outwit” the variants.

  • Is the Johnson & Johnson vaccine going to be available soon and will it be used in Massachusetts?

    • Johnson & Johnson vaccine rollout depends on the FDA review, then on recommendations from ACIP (part of CDC), then on acquisition by the federal govt, then on allocation to the states.​​​​​

​​​​​​Who/When to Get Vaccine?

  • How long after getting another vaccine (e.g. flu, shingles) should I wait before I get COVID vaccine?
    • CDC recommends 14 days, with the rationale that you don’t want to confuse side effects from the COVID vaccine with side effects from any other vaccine (particularly shingles, which can make people feel pretty sick).  Pragmatically: get the COVID vaccine whenever it is available to you, regardless of when you got other vaccines.
  • Can pregnant women get vaccinated?
    • Yes.  The clinical trials of Pfizer and Moderna excluded pregnant women and therefore we don’t have specific efficacy and safety data in this population.  Animal studies have show no adverse effects on developing fetus from mRNA vaccines.  Studies are being conducted in real time of safety (e.g. through V-SAFE/CDC) on pregnant women who are receiving vaccine now.  There is not a compelling medical reason to believe that the mRNA vaccine would be either dangerous or less effective in a pregnant woman.   
  • Can I get vaccine if a received passive antibody therapy or other treatment for COVID?
    • Yes, but passive antibody therapy (monoclonals) is expected to impair your body’s ability to produce an immune response to vaccine for 90 days.  So those who got monoclonal antibodies should wait 90 days until they get vaccinated. 
    • Other COVID therapies (remdesivir, dexamethasone) have no bearing on vaccine efficacy – folks can get elect to get COVID vaccine as soon as recovered from COVID illness.
    • The duration of immunity following COVID infection is presumed to be 6+ months.  So there is no rush to get vaccine for those who have been recently infected – they are protected. 
  • Should I get vaccinated if I already had COVID? If so, how long after?
    • The duration of immunity following COVID infection is presumed to be 6+ months.  So there is no rush to get vaccine for those who have been recently infected – they are protected.  However, folks who have had COVID can elect to get vaccine as soon as it is available to them. 
  • If someone has an underlying health condition or is immuno-compromised, is it safe for them to take the vaccine?
    • Comorbidities: The clinical trials of the vaccines included a large proportion of people with underlying conditions such as diabetes, heart disease, lung disease.  It was safe and effective these people.  
    • Immunocompromise: Clinical trials excluded people with severe immunocompromise (receiving chemotherapy, AIDS, etc) so we don’t have definitive data.  These folks are at higher risk for severe COVID disease, so we recommend that they get COVID vaccine ASAP, knowing that immunocompromise may make it less effective. 
  • Can you get both vaccines?  (e.g. Pfizer for 1st dose, Moderna for 2nd)
    • Mixing vaccines is not recommended (just because of lack of data), but if it comes down to getting a mis-matched pair or getting no 2nd dose – go for the mismatch!
  • Do we have any idea when this will be offered to children? Is it safe for children? Or do we just not know yet?
    • Pfizer vaccine authorized for age 16+, Moderna for 18+. Studies in children ongoing, with an anticipated timeline of ~months. ​Studies in children are needed to understand optimal dosing. Children are clearly at lowest risk for severe disease for COVID, so less urgency.
  • Would there be a problem for people undergoing chemotherapy and getting the vaccine
    • ​​​​​​​​​​​​​​Chemotherapy lowers someone's immune response, so people on chemo may not mount as effective an immune response as people who are not on chemo. ​Otherwise said: people on chemo should definitely get vaccine, discuss the optimal timing of vaccine administration (vis a vis their chemo treatment), but may not get as much protection.  Some protection is better than none and people on chemo are at high risk of severe disease.
  • Can the vaccine be given in a location other than the arm (gluteus maximus, for example), for person who has lymphedema in both arms?
    • Yes, as long as it is administered intramuscularly.

Side Effects

  • What can someone expect after taking the 1st vaccine? How will they feel? What reactions may they have? ​​​​​​
    • Almost everyone will have arm pain.  Other reactions are less likely. 
  • What can someone expect after taking the 2nd vaccine? How will they feel? What reactions may they have?
    • Most people will have some symptoms – your immune system has already been primed by the first dose and is ready to rock!  These symptoms are normal and indicate that your immune system is doing what it needs to do.
    • Common symptoms: arm pain and fatigue (in most), headache, muscle aches and fever (in ~half).  Symptoms are often prominent enough that you might have to stay home from work/school/usual activities but resolve within 48-72h. 
  • Can I get COVID-19 infection from the vaccine?
    • No.  Unlike other vaccines which are killed (“attenuated”) forms of a virus, the COVID vaccines do NOT include the virus itself and therefore can’t result in infection. 
  • Will vaccines cause fertility issues?
    • ​​​​​​​​​​​​​​There is NO credible evidence to support this claim. 
  • Are there any interactions with medications?
    • Not really.  Only in the sense that if you are receiving a medication that impairs the immune response (eg for rheumatoid arthritis, inflammatory bowel disease or cancer), you should try to time getting the vaccine when your immune system is at its strongest (so it can respond the best to the vaccine).    
  • If you have COVID but are asymptomatic and get vaccine, what will happen?
    • If COVID infection has already been established at the time vaccine is administered, the infection will proceed as it normally would have.
  • ​Is there a plan in place to assist elderly people who live alone (have no helper with them at the vaccine site), to follow up after the second shot to make sure they are not having serious issues?
    • ​​​​​​​​​​​​​​In general, people feel more ill (fatigue, HA, muscle pains, fever) in the 48h following the 2nd dose than following the first dose. Interestingly, older people have FEWER side effects from the vaccine than younger people. However, we should partner with primary care to follow-up on folks after 2nd dose.


  • How long do vaccines last?  ​​​​​​​
    • Unclear at this time, as neither the virus nor the vaccines have been around long enough to definitively state duration of protection.
    • Best available evidence is that immunity from natural infection lasts at least 6mos. 
    • The answer will depend in part on what happens with variants (e.g., vaccine immunity could be reduced if vaccine-resistant variants become widespread).
  • Herd immunity? When will it be reached?
    • The million dollar question.  Probably somewhere north of 70% of the population immune from natural infection and vaccine.  We are still somewhere in the 30-40% range. 
  • I have received vaccine. Do I still need to wear a mask?
    • In public?  Yes. This is a public health strategy that applies to everyone.  It puts others at ease, since they don’t know you have been vaccinated.  Also, it is not definitively known whether the vaccine prevents people from having asymptomatic infection that they could transmit to others (but preliminary evidence suggests transmission is unlikely after vaccines). 
  • Once someone is vaccinated, can they still transmit the virus to others who have not yet been vaccinated?
    • We don't yet have data to definitively answer that question. Initial data - and experience from prior vaccines - points to the likelihood that vaccinated persons will NOT transmit virus. That is, vaccine is likely to be good not only in preventing symptomatic infection but also in asymptomatic infection.
    • It is not definitively known to what degree mRNA vaccines prevent asymptomatic transmission. It is known that they are >95% effective in preventing symptomatic infection and that preliminary data suggest that they also prevent transmission (asymptomatic infection).
    • The main endpoint in the trials was symptomatic infection (ie, clinical disease) rather than infection (ie asymptomatic shedding of virus). However, the Moderna trial did do surveillance for asymptomatic infection and showed efficacy in preventing transmission.
  • Are vaccines effective against the new strains?
    • Modern and Pfizer weren’t tested at a time when the variants were circulating, so we don’t know.  Johnson & Johnson, Novavax, and Janssen all showed lower effectiveness in South Africa – suggesting that vaccines are less effective against the South African variant. 
  • Does blood type have anything to do with vaccine effectiveness?
    • No.
  • After vaccination, will COVID antibody test be impacted? 
    • Most of the antibody tests available currently test only for antibody induced by natural infection (antibody to nucleocapsid protein), not antibody induced by vaccine (antibody to spike protein).  So you will probably not test positive by antibody after vaccine alone.  This is changing, though – you need to find out what the specific antibody test your lab uses tests for. 
  • Once I get the vaccine, how and where can I obtain an antibody test to verify that I am in the 95% that have immunity with the vaccine?
    • Such antibody tests are neither recommended nor widely available. 
  • How long after the second dose can I consider myself fully protected? What is known about the prevalence of the resistant or more contagious COVID strains in our area?
    • 95% protection occurs 14 days after 2nd dose of mRNA vaccines (Moderna/Pfizer)
    • In general, the US has limited lab capacity to do the type of virologic surveillance that is needed to detect the variants.  The UK variant has been detected in 33 states, but this is likely an under-representation based on under-surveillance.
  • What % of effectiveness is the first shot?
    • ​​​​​​​​​​​​​​Protection starts to kick in at 12 days after the first dose. By the time of the second dose, protection is 80% or higher. By 14 days after 2nd dose, protection is >95%​​​


Employer-Related Questions

  • Is it true that when a vaccine is under EUA an employer can't "require" employee vaccination?
    • Yes, a vaccine that is not full approved by the FDA cannot be mandated by an employer.

How to get vaccine/shortage

  • How do you sign up for a vaccine?
  •  Is there a shortage of the vaccine supply in MA?
    • At this time, yes.  It is expected this will ease as both production of current vaccines ramp up and new vaccines become available
  • For drive-thru vaccination clinics, is there observation time?
    • Baystate will not be conducting drive through clinics.  That said, the advised observation time is 15 minutes.
  • What about vaccinations for home-bound residents?
    • We are actively working on a plan for such individuals
  • Can you get shots in two different states?
    • This not advised—states track vaccinations
  • Can you choose the vaccine?
    • If the supply and arrangements favor it, you might.  Mostly it is limited to what is available so choice may not be an option.
  • I am 69, will they allow the next eligible group of people to set up appointments before they are eligible? Or do we have to wait and try to sign up all at once. Or will there be a notice that the registration is open?
    • There is not pre-registration at this point.  It will therefore be more of the situation in the latter questions.  There should be an announcement as each eligible group comes up.
  • Since the CDC counts thalassemia as a co-morbidity why isn't it listed as such in MA?
  • When are Early Childhood Educators allowed to receive the vaccine? Does this also include those in accessory positions (cook, janitor, book keeper - all in building with children)?
    • These are Phase II Group 3 which has not opened up yet.
  • Will the state be opening more localized vaccine sites? ​​​​​​