Vaccination FAQs

Updated June 17, 2021.

The state-run, fixed vaccination sites are now only open for second doses in June 2021. All of them will close on June 30, 2021 but hospital vaccination sites still open to the public are listed here.

Walk-in vaccinations are now available at many local pharmacies and healthcare providers' offices. For a list and contact information, click here. (To download a PDF of the list, click here.)

If you have language issues that prevent you from understanding registration instructions for the COVID-19 vaccine, please contact Kim McNamara at the Portsmouth Health Department or call(603) 610-7273. If you get voicemail, please be sure to leave a message​.

For the latest CDC information about the COVID-19 vaccine, including "Key Things to Know," click here.

Everyone now receiving the first dose of a 2-dose vaccine receives a vaccination card that includes a scheduled appointment for Dose 2. All they need to do is show up for Dose 2.

Homebound individuals are being reached by the VNA and other home healthcare providers. But if you do not have a home healthcare provider, and are over 65 or have two qualifying medical issues, call 2-1-1 to schedule a vaccination.

For those unable to schedule their first appointment online, the 211 Hotline remains available, 7 days a week, 6 am to 10 pm.

When calling 2-1-1, you will be given a choice: "For questions related to COVID-19, press 1” and “for any other NH 2-1-1 related questions, press 2”. Once in the COVID-19 directory, you are offered additional choices: 

1)      If you want to schedule a vaccine

2)      For testing, Isolation and quarantine questions

3)      For vaccine questions,  Note: ​To cancel a scheduled appointment, choose this option and then tell the agent who answers the phone to put you the through to the scheduler, who can cancel and reschedule your appointment.

4)      General COVID questions

5)      If you are a healthcare provider reporting positive cases, or to speak with an agent

6)      If you are returning a call

Those with medical conditions that qualify them for Phase 1B vaccinations should contact their health care provider as only medical professionals can schedule their appointments.

Once you have registered, you will receive an email from the state's registration site for scheduling your actual appointment.

I need to reschedule my vaccination appointment – what should I do?

If you cannot make your scheduled vaccination appointment use VINI ( to reschedule online, or call 211. If you do not have access to VINI, call “211” as soon as possible to cancel and reschedule.  When you call, follow the voice prompts for COVID Questions and for appointments. It is very important that you cancel as soon as you know you cannot make your appointment so that vaccine does not go to waste.

I got my vaccine@

Where can I get the vaccination?

The state's original 11 fixed vaccination sites will close on June 30. Click here for other hospital vaccination sites that are open to the public. There are also "closed pod" clinics, mobile vaccination providers and other capabilities in operation. Distribution is now being handled much the same as flu shots -- through your healthcare provider and pharmacies. For more information on vaccination sites and other vaccination details, click here

How much will it cost to get the vaccine?
Nothing. Tax dollars funded the vaccine research and production so the vaccine you receive is free.

Is the vaccination painful? 
The vaccination involves an injection into your upper arm with a thin needle. The shot itself will feel the same as other vaccinations you have received. 



Studies show that COVID-19 vaccines are safe and very effective at preventing hospitalization and death from COVID-19. Now that there are authorized and recommended COVID-19 vaccines in the United States, accurate vaccine information is critical. COVID-19 vaccinations are critical to stopping the pandemic. None of the COVID-19 vaccines contain the live virus that causes COVID-19 so a COVID-19 vaccination cannot give you COVID-19. While more COVID-19 vaccines are being developed as quickly as possible, routine processes and procedures remain in place to ensure the safety of any vaccine that is authorized or approved for use. Safety is a top priority, and there are many reasons to get vaccinated

What is a vaccine?

A vaccine is a substance used to stimulate the production of antibodies and provide immunity against one or several diseases without causing the disease. Vaccines are in a category of substances known as antigens.

What are antigens?

An antigen is a substance foreign to the body that, when recognized by the body’s immune system, brings about a response to rid the body of the antigen and either prevent or minimize illness.  These responses, called immune responses, include directly “killing” the antigen, bringing about the production of antibodies to neutralize the antigen, and producing “memory cells” so that if the antigen is detected in the future it can be destroyed by the immune system.

What are the different types of vaccines for COVID-19?

Several different pharmaceutical companies started working to develop a COVID-19 vaccine in the spring of 2020.  FDA’s Center for Biologics Evaluation and Research [CBER] ensures that FDA’s rigorous scientific and regulatory processes are followed by those who pursue the development of new vaccines. The vaccines that have been made public include the mRNA vaccines made by Pfizer and Moderna. The Adenoviral vaccine made by Johnson and Johnson was approved on February 28 and reaffirmed on April 23. 

What is an mRNA vaccine?

This type of vaccine uses viral messenger RNA (mRNA) to teach the immune system to recognize viruses as antigens. mRNA, found in all cells, provides cells with instructions on how to make proteins (among other functions). In the case of activating the immune system, the mRNA instructions cause the cell to make a protein that is very similar to the virus or one of its parts. Once this protein is made and “displayed” on a cell surface the body then recognizes this altered cell as foreign (an “antigen”) and begins to produce antibodies against the antigen. This technology DOES NOT use a live or weakened form of the virus, nor does it affect the nucleus or DNA of the cell. These mRNA vaccines do not and cannot infect those who receive them with COVID-19. While mRNA vaccines represent a new technology, using mRNA to produce antibodies is not new; this approach has been studied in laboratories for many years.

How do the COVID-19 mRNA vaccines work?

The COVID-19 mRNA vaccine is first injected into a muscle in your upper arm. The vaccine then enters nearby cells and instructs them to make a piece of the COVID-19 “spike protein” that plays a role in anchoring the virus to respiratory and other body tissues. Once the mRNA instruction is received by your cells, those cells start manufacturing the spike protein and display it on their surface. The presence of the “foreign” spike protein on the surface of the cell causes your body to produce antibodies against the spike protein. Should you become exposed to the virus, these antibodies will recognize the COVID-19 spike protein and fight the virus or minimize its infectiousness.

What is an adenoviral vaccine?

An adenoviral vaccine uses an adenovirus -- common viruses that typically cause colds or flu-like symptoms -- to activate an immune response. This technology is the basis for many vaccines that are already in widespread use. These vaccines insert a gene that codes for a protein into an unrelated adenovirus that has been modified and rendered harmless. Once rendered harmless this adenovirus with the inserted gene will not and cannot infect anyone with COVID-19.  Once administered in the vaccination, the adenovirus attaches to a cell surface, moves into the cell, enters the cell nucleus, and incorporates into the cell DNA. This causes the cell nucleus to “read” the inserted gene and instructs its natural mRNA to begin making the protein instructed by the inserted gene. The Johnson and Johnson vaccine is an adenoviral vaccine.

How do the adenoviral COVID-19 vaccines work?

The gene for the coronavirus “spike protein” is inserted into an adenovirus that has been modified to render it harmless (it cannot cause COVID-19).Once administered into a muscle in the upper arm this modified adenovirus enters a cell, travels to the nucleus, and inserts the gene for making the spike protein into the host cell DNA. The host cell “reads” the gene for the COVID-19 spike protein and copies the instructions for making the spike protein onto natural mRNA. The mRNA then directs the cell’s protein-building structures to produce the COVID-19 spike protein. The manufactured spike protein travels to the surface of the cell where it is recognized by the immune system as “foreign” and starts producing antibodies against the spike protein. Should you become exposed to the virus, these antibodies will recognize the COVID-19 spike protein and eradicate the virus or minimize its infectiousness.

How are the two vaccines that use mRNA different?

The Pfizer and Moderna mRNA vaccines are composed of mRNA containing the instructions for making the COVID-19 spike protein so that once the vaccine is taken into a cell the protein building instructions are already in place and spike proteins can be made by the cell protein building structures.

The adenoviral vaccines contain the instructions for building the spike protein on a gene that has been incorporated into a modified adenovirus. Once this vaccine enters the cell it travels to the cell nucleus where it inserts the gene for making the spike protein into the cell DNA. The cell DNA then transfers these instructions to its own mRNA. This mRNA then leaves the cell nucleus and travels to the cellular structures that build the spike protein.

For more information including drawings showing how adenoviral and mRNA vaccines work, visit:

New York Times, How the Moderna Vaccine Works 
New York Times, How the AstraZeneca Vaccine Works
USA Today, How New RNA Technology Was Used to Create COVID-19 Vaccines


All three COVID-19 vaccines are now available in NH.

ANYONE over 12 (only the Pfizer vaccine is approved for those aged 12-17), regardless of residence is eligible to sign up to receive the vaccine. Go

Where will I get the vaccination?

The state has set up 20 fixed sites. Other mass vaccination sites, "closed pod" clinics, mobile vaccination providers and other capabilities are also deployed. For more information on vaccination sites and other vaccination details, click here.

Does it make a difference which vaccine I receive?

No. The FDA, CDC and NH DHHS stress that all three vaccines are safe and highly effective for preventing severe illness, hospitalization and death. Residents should take the first opportunity offered to be vaccinated.

What about the problems from the Johnson & Johnson (Janssen) vaccine (update as of April 23, 2021)?

After a few cases of rare blood clotting complications, J & J vaccine use was temporarily halted so that experts at the FDA and CDC could investigate and develop treatment guidelines for this extremely rare complication.  On April 23 the guidelines were finalized and along with the recommendation to resume use of the J&J vaccine as safe and effective. The committee also encouraged that those choosing the J&J vaccine be aware that there is an extremely low risk of developing a rare side-effect called TTS (Thrombosis-Thrombocytopenia Syndrome) that causes both blood clotting and decreased platelets in the blood.

  • This rare side-effect was observed in 15 cases out of 8.9 million J&J doses administered in the US.
  • Of those cases, 13 were women between 18 and 49 (a rate of 7 in 1 million).
  • FDA guidance is that J&J is safe and effective for that population group
  • Members of the group can choose one of the other two vaccines if they prefer.

Side-effects that might suggest TTS include headaches that occur within 6 to 15 days after vaccination – NOT within 2-3 days as headaches are seen as a normal side-effect from receiving the J&J vaccine.

Women who have a history of the blood-clotting syndrome HIT should consider either Moderna or Pfizer vaccines.

Those who are on an aspirin or other anticoagulant regimen may safely receive the J&J vaccine; but otherwise, people should not take aspirin or other anticoagulant before any vaccine.

Can I get one dose of one of the vaccines and the second dose of the other 2-dose vaccine?

No – while both the Pfizer and Moderna mRNA vaccines require two doses, the manufacturing process of each vaccine was different and proprietary for each company. Since the vaccines differ in composition, storage, and time between doses, people must get the same vaccine for both doses.

What if I miss the second vaccination?

The two currently approved vaccines are: 21 days between shots for Pfizer and 28 days between shots for Moderna. The card you receive after the first vaccination will list which vaccine you received and when your second dose is scheduled.

Should you miss your appointment or need to reschedule for any reason, be sure to get the second shot as soon as possible to ensure the benefit of full immunity. Regarding timing in between the first and second vaccine: those who are concerned they have not been able to schedule their second vaccine within the 21 or 28 day interval should know that these intervals are a minimum amount of time necessary between each dose. No maximum interval has been established for the second dose. NH DHHS and the CDC feel quite confident that there is the same amount of protection even if the time interval between the first and second dose is longer than 21 or 28 days. 


NH DHHS Vaccine Comparison 12/31/20

For the complete Update (12/31/20) from NH DHHS, click here.

Is the vaccination painful?

The vaccination involves an injection into your upper arm with a thin needle. The shot itself will feel the same as other vaccinations you have received.

What are the side effects?

All vaccine trial participants reported minor side effects common to many vaccinations including a sore arm or feeling poorly, fatigue, or tired for a day or two after the shot. Other reported side effects included headache, fever and chills, and other muscle aches/pain primarily after the 2nd shot that lasted a day or two. Some vaccine trial participants treated these side effects with pain medication, but you are advised not to take pain medication before receiving Dose 2, in anticipation of side effects, as that would diminish the effectiveness of the vaccine. Side effects show that the vaccination is working -- your body is responding. The percentage of participants experiencing these side effects depend on the vaccine administered. For specific percentages detailed in the report, click here.

There have been isolated reports of more severe side effects including allergic reactions. You should discuss getting the vaccine with your health care provider to determine if you are at risk for a more severe reaction. You will also be asked to stay for 15-30 minutes after receiving the vaccine to monitor for any serious side effect and to receive the vaccination in a place capable of providing prompt emergency care.

There have been isolated reports of a rare blood clotting disorder associated with the J & J vaccine.  Refer to the earlier question for more information.

What is known about the long term complications of COVID-19 What is a “COVID-19 Long Hauler?” Does the vaccine help prevent this complication?

Significant numbers of people continue to experience troublesome symptoms for 3 or more months following initial COVID-19 infection. Sometimes the symptoms are new and sometimes they continue to linger beyond the usual recovery period.  “COVID-19 long hauler” is the term used to describe this phenomenon, which can be quite debilitating. The medical term is Post-Acute Sequelae of SARS-CoV-2 infection or PASC. The best way to prevent long term complications is to avoid infection in the first place by being vaccinated and following the guidelines for mask wearing, physical distancing, and handwashing.

What should I do if I have a bad reaction to the vaccine?

If you have a bad reaction, you should notify your primary care provider immediately.  If you are having trouble breathing, notice any sudden swelling (especially of your face or tongue), or feel faint after you have received the vaccine and left the facility, call 911 for immediate emergency care.

The CDC and FDA encourage the public to report possible side effects (called “adverse events”) to the Vaccine Adverse Event Reporting System (VAERS)external icon external icon. This national system collects data to look for adverse events that are unexpected, appear to happen more often than expected, or have unusual patterns of occurrence. Reports to VAERS help the CDC monitor the safety of vaccines. Safety is a top priority.

The CDC is also implementing a new smartphone-based tool called “v-safe” to check-in on people’s health after they receive a COVID-19 vaccine. When you receive your vaccine, you should also receive a v-safe information sheet telling you how to enroll in v-safe. If you enroll, you will receive regular text messages directing you to surveys where you can report any problems or adverse reactions you have after receiving a COVID-19 vaccine.

I have a history of allergies – should I get the vaccine?

In all cases, if you have any concerns or questions about the vaccine, you should ask your health care provider. Since its public rollout both vaccines have been associated with an immediate allergic reaction in a very small number of people. These reactions have occurred within the first 30 minutes after receiving the shot; for this reason, those with severe anaphylaxis to anything (drug, food, insect bites, etc. should be informed of the risk and monitored for 30 minutes rather than 15 minutes after vaccination to be sure you do not have a serious allergic reaction.

Right now, it is highly recommended that persons who have had an anaphylactic reaction to any drug, food or other vaccine NOT receive the vaccine. Both vaccines have only one contraindication: known history of a severe allergic reaction to any component of the vaccine. The DHHS guidance says those with severe anaphylaxis to anything, should be informed of risk and monitored for 30 minutes rather than 15. It does not say they shouldn't get the vaccine.

If I have had COVID-19 do I need to get a vaccination?

Yes! According to the CDC, even people who have already gotten sick with COVID-19 may benefit from the vaccine.  If you were treated for COVID-19 symptoms with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting a COVID-19 vaccine. Talk to your doctor if you are unsure what treatments you received or if you have more questions about getting a COVID-19 vaccine.

COVID-19 can lead to serious illness and long-term complications, even in younger people and those without underlying medical conditions. It is possible for someone who has already had COVID-19 to be re-infected, though this is not common.

It is not yet known how long natural immunity to COVID-19 lasts or if the strength or duration of natural immunity varies based on the severity of the initial illness. 

If I received monoclonal antibodies or convalescent plasma to treat COVID-19 should I get a vaccination?

Based on the research on these therapies, as well as evidence suggesting that reinfection is uncommon in the 90 days after initial infection, vaccination should be deferred for at least 90 days, as a precautionary measure until additional information becomes available, to avoid potential interference of the antibody therapy with vaccine-induced immune responses.

I have heard that some people develop COVID-19 after getting their first shot. if this happens should I reschedule my second shot?

Full immunity to COVID-19 after receiving the vaccination takes time to develop. Early studies of the Moderna and Pfizer vaccines reported about 50% protection after the first shot. This means that once your immune system began to develop antibodies to COVID-19 you still have a 50-50 chance of contracting the infection after the initial shot. This is one of the reasons it is important to continue to wear a mask, physically distance, and wash your hands frequently, per CDC recommendations.

If you develop COVID-19 after your first shot, you should delay the second shot until you have recovered from the acute illness (if you have symptoms) and have been met the DHHS criteria for ending isolation.

I’m pregnant and/or breastfeeding – should I get a vaccine?

You should discuss vaccination with the person providing your pregnancy or breastfeeding care, but research has determined that the vaccine is safe and effective for pregnant and breast-feeding women.

I have chronic health problems that put me at higher risk should I get COVID-19, should I get the vaccine?

It is important to discuss with your primary care provider your potential risk should you develop COVID-19 and the benefit you might receive from vaccination. Those with chronic health conditions including asthma, COPD, diabetes, heart disease, and obesity are at higher risk of becoming seriously ill should they contract COVID-19.  Persons with pre-existing conditions are more likely to need hospitalization, oxygen support, and sometimes intensive care including a mechanical ventilator. The vaccine trials have included people with pre-existing conditions for exactly this reason; and the vaccines have been demonstrated to be safe in trial participants with pre-existing conditions.

I don’t want to get a vaccine, what other ways can I protect myself from contracting COVID-19?

A good place to start for accurate information on your risks, whether or not you choose to become vaccinated, is with your primary care provider. Your PCP has all the health information you’ve shared available to carefully and thoughtfully help you consider your benefit and risk for vaccination.

Whether you choose to be vaccinated with a COVID-19 vaccine or not, you should continue to follow all recommendations for avoiding infection and if infected, not spreading the infection to others. Those recommendations are often referred to as the 3 C’s: avoid crowded places, contact with infected persons, and closed spaces and, the 3 W’s: Wear a mask, Wash your hands frequently, and Watch your distance—maintaining 6’ apart from others (also called physical distancing).


A recent survey by the Pew Research Center found that more Americans (60%) say they would probably or definitely get the vaccine when it is available to them – up from the 51% who said so in September. But many Americans still have questions, and these suggestions are offered to help you encourage your families, friends and community members to get the vaccine. Read the full article here.

The vaccine is the key tool for ending the pandemic and relaxing the restraints on "normal" life.

All three vaccines are safe and effective -- and went through full clinical trials before being approved by the FDA and recommended by the CDC.


Once vaccinated how long does it take to be protected?

In general, it takes 14 days after the last vaccine shot to have robust immunity. (Pfizer and Moderna vaccines each require two shots). Before that time, you may have some protection against COVID-19 but it is not possible to predict how protected you are before completing the vaccination schedule.

Once I’m vaccinated, do I still need to wear a mask?

On May 13, 2021 the CDC announced that fully vaccinated people could go without masks. However unvaccinated people are still at risk of substantial community transmission in most parts of the country, including in NH. The Portsmouth Mask Ordinance is in effect through June 30, 2021. This ordinance requires mask wearing whenever 6’ physical distance cannot be maintained in both indoor and outdoor settings.

Individual businesses and localities are permitted to require masks under the Governor's new "Universal Best Practices" guidance.

If I’m vaccinated, and all my friends and family are vaccinated, can we hang out together without masks?

Yes – BUT: There are four questions to ask if you want to spend time indoors with others, being mindful of their risk:

  • Are you vaccinated?
  • Is everyone else in the room vaccinated?
  • What’s the level of spread in the community?
  • Is someone in the room at high risk?

Even if everyone in the room is vaccinated, you need to think about the last two questions. The vaccine gives you about 90-95 percent protection. You also need to think about your odds of coming into contact with the virus. A 5-10 percent risk of infection when the virus is raging is still a significant risk and not low enough when the cases remain high in your community.

The final question — is someone in the room at high risk — is also important. Even if a high-risk person is fully vaccinated, you need to take extra precautions when virus case counts are high in your community. It is important to remember that the vaccine may not be 90-95 percent effective in every single person — an older person or someone with a less efficient immune system might get less protection from the vaccine than a young, healthy person. 

Once I have received the full vaccine will I need a booster shot?  Will I have to be vaccinated every year, like with the flu shot?

At this time, it is not known how long immunity will last, not only from the vaccines, but also for those who developed COVID-19 and natural immunity from having the disease. As the vaccine trials progress and more information is collected, there will be better guidance as to the length of protection and/or the need for additional shots.


Do you have additional questions about the COVID-19 vaccinations in NH?


For more information on the vaccines, visit: