Post-Vaccination FAQs

Updated June 22, 2022

Congratulations on being vaccinated! The CDC (and NH DHHS) considers you “fully vaccinated” once you are 14 days past your last shot. Here are some answers to questions frequently asked by those who have been fully vaccinated:

Q. What is a "breakthrough" infection?

A. Vaccines help the body fend off infection by building defenses against the virus in the immune system. "Breakthrough" is the shorthand word for cases of COVID-19 that develop in fully-vaccinated people. All three COVID-19 vaccines are working as expected, based on number and severity of infections in vaccinated vs unvaccinated individuals. For more information from the CDC, click here.

Breakthrough infections in NH: As of Oct. 22, 2021, NH DHHS had identified 2,441 breakthrough cases in the state, 3.4% of all cases. This includes 47 confirmed hospitalizations as a result of breakthrough cases, and 40 deaths. Hospital staff say many of those hospitalized with breakthrough cases had other underlying health conditions that made them more at risk for COVID-19. [Source NHPR]

Q. How do vaccines work and why are fully vaccinated people still getting COVID-19?

A. The effectiveness of vaccination, first discovered hundreds of years ago, is that by giving the body a safe way to create and build up natural defenses against infection, the body will recognize the cause of the infection (for example, a virus) the next time it encounters it. We now know that vaccination causes the body to produce antibodies that fight specific infections – the flu, smallpox, polio and COVID-19, for example -- and also “memory cells” – B cells and T cells – that are triggered when a virus “invades.”

People who are fully vaccinated can contract COVID-19 when there is a lot of virus circulating – “high community transmission” – and when a new variant is different enough from the original virus to get past the antibody defenses. (Although the three vaccines in use in the US were developed before the Delta variant appeared, so far, the variants, including Delta, are close enough to the original virus that the antibodies and memory cells do recognize it.)

Many of the symptoms for “flu” diseases (“the flu” in winter, or COVID-19), such as runny nose, cough, upset stomach, headache, fever, etc. are the evidence of the body’s efforts to fight it off. Therefore, when someone symptoms and tests positive for “breakthrough” COVID-19, that is direct evidence that the vaccine is working. Further evidence comes when most vaccinated patients successfully fight off the virus after two or three days and are not overwhelmed. In unvaccinated patients, the symptomatic fight is more likely to become harder and harder and patients are more likely to end up hospitalized with severe illness, requiring external oxygen and ICU care and might even die. However, there are still some rare cases of fully vaccinated people who succumb to severe “breakthrough” infection.

Q. Does vaccine protection fade?

A. Vaccines lead to the production of antibodies, B cells and T cells which all contribute to immunity. Antibodies circulate at higher concentrations immediately after vaccination; but they diminish as time goes by – or our bodies would be so full of antibodies for all the diseases we’ve encountered and survived that there wouldn’t be room for much else in our blood. As the antibody intensity subsides, the B and T memory cells wait in reserve in case a new infection – as from COVID-19 – enters the body. When that happens, because they are programmed to respond to that specific virus, they rush into action to fight the invading virus.

Studies in the UK of those who have received the COVID-19 vaccines show that, although there is some waning after six months, antibody and memory cell protection is holding up quite well, especially in those who have healthy natural immune systems. For those who are “immunocompromised” (have a less robust natural system) and for those elderly whose immune systems are not as strong, the body’s response to the vaccine is weaker. That is why recent guidance has suggested that the immunocompromised and seniors might need a third dose of the Pfizer or Moderna vaccines. This means that for those individuals, the COVID-19 regimen is three doses, not two. Two doses of Pfizer or Moderna seem sufficient for everyone else at this time.

If a more resistant variant emerges, the design of the mRNA vaccines from Pfizer and Moderna allow them to be ‘tweaked,’ so that third doses with those formulations prompt the body to produce a stronger immunity to that variant.

For a more detailed explanation of how the COVID-19 vaccine is working, see this article in The Atlantic.

Q. How common is “breakthrough” infection?

The CDC is tracking the breakthrough infections reported by 20 states (not including NH). 

According to the CDC tracking program, as of August 30, 2021, more than 173 million people in the United States had been fully vaccinated against COVID-19. Only 10,471 experienced “breakthrough” cases that led to hospitalization (a probability of 0.006 in 100, or roughly 1 in 5,000). The CDC cautions that this is a “snapshot” and probably is an undercount because it does not include asymptomatic breakthrough cases that were not reported. It is important to understand that these individuals with breakthrough cases may transmit the virus to others. This is why the CDC recommends that, even if you are fully vaccinated, you wear a mask indoors in public if you are in an area of substantial or high transmission.

During the same time, CDC received reports from 49 U.S. states and territories of 2,437 patients with COVID-19 vaccine breakthrough infection who died: a probability of 0.001 in 100 (1 in 71,429) chance of dying from a breakthrough infection by COVID-19.

Q. What about booster shots of COVID-19 vaccines?

A. On September 1, 2021, the U.S. Department of Health and Human Services (HHS) with the CDC offered guidance on “booster shots” of COVID-19 vaccine,   CDC recommends moderately to severely immunocompromised people consider receiving an additional (third) dose of an mRNA COVID-19 vaccine (Pfizer-BioNTech or Moderna) at least 28 days after the completion of the initial 2-dose mRNA COVID-19 vaccine series. However, CDC says “not immediately” for “booster doses” -- another dose of a vaccine that is given to someone who built enough protection after vaccination, but whose protection may have decreased over time. People might start receiving a COVID-19 booster shots beginning in the fall (8 months after receiving the second Pfizer or Moderna shot); but this is subject to authorization by the U.S. Food and Drug Administration and recommendation by CDC’s Advisory Committee on Immunization Practices (ACIP). FDA is conducting an independent evaluation to determine the safety and effectiveness of a booster dose of the mRNA vaccines. ACIP will decide whether to issue a booster dose recommendation based on a thorough review of the evidence.

Q. Now that I am fully vaccinated, why is the CDC still recommending I wear a mask indoors if I'm fully vaccinated?

A. Masks are very effective in helping prevent the spread of COVID-19. As the Delta variant is more contagious and has severe impacts on the unvaccinated, masks keep infected persons from transmitting the virus and they keep others from picking up the virus. Especially in places with less air circulation than outdoors.

  • Get tested if experiencing COVID-19 symptoms.
  • Get tested 3-5 days following a known exposure to someone with suspected or confirmed COVID-19 and wear a mask in public indoor settings for 14 days after exposure or until a negative test result.
  • Take precautions based on the vulnerabilities of the unvaccinated people in the household – even if they are not present during the visit.
    1. If the unvaccinated people are from a single household with no one at risk of severe COVID-19, no precautions are needed. For example, fully vaccinated grandparents can visit indoors with their unvaccinated healthy daughter and her healthy children without wearing masks or physical distancing, provided none of the unvaccinated family members are at risk of severe COVID-19.
    2. If any of the unvaccinated people or their household members are at increased risk of severe COVID-19, everyone should take precautions including wearing a well-fitted mask and staying at least 6 feet away from others. For example, if a fully vaccinated individual visits with an unvaccinated friend who is seventy years old and therefore more at risk of severe disease,  the visit should take place outdoors, wearing well-fitted masks, and maintaining physical distance (at least 6 feet).
  • Take precautions if visiting unvaccinated people from multiple households. As there is a higher risk of COVID-19 transmission among them, all people involved should take precautions including wearing a well-fitted mask and staying at least 6 feet away from others. For example, if fully vaccinated grandparents are visiting with their unvaccinated daughter and her children and the daughter’s unvaccinated neighbors come over, the mixing of two unvaccinated households poses a higher risk (even if the vaccinated grandparents were not present). The visit should take place outdoors, wearing well-fitted masks, and maintaining physical distance (at least 6 feet).

This NHDHHS graphic may help:

Risk for vaccinated people

When in doubt -- maintain masking and physical distancing.

Everyone, regardless of vaccination status, should adhere to current guidance:

    • Avoid medium- or large-sized in-person gatherings
    • Follow local guidance restricting the size of gatherings.
    • In public places, take precautions to reduce spread, including wearing a well-fitted mask, maintaining physical distance and washing hands frequently.

In addition, fully-vaccinated people should continue to:

  • Get tested if experiencing COVID-19 symptoms
  • Follow guidance issued by individual employers
  • Follow CDC and health department travel requirements and recommendations

While the vaccines are designed to keep a vaccinated person from developing a case of COVID-19 that requires hospitalization or intensive care, they do not necessarily prevent all infection. It is not yet known and further research is being conducted to determine whether the vaccine prevents the spread of the virus. As NH DHHS emphasizes, “It remains possible that people who are fully vaccinated or previously infected could still acquire asymptomatic COVID-19 infection, or attenuated (milder) COVID-19. Therefore, even people who are fully vaccinated or previously infected need to continue to practice physical distancing, avoid social groups and gatherings, and wear face masks at all times when in public places and facilities. Healthcare providers should continue to follow all recommended infection control and personal protective equipment (PPE) guidance.”

I lost my proof-of-vaccination card. Now what? 
All vaccination records are kept on file in the CDC National Health Interview Survey (NHIS) system. NH DHHS advises that you can replace a lost vaccination card in either of two ways:

  • Download and complete this vaccination card replacement request form . Note that the completed form MUST BE NOTARIZED before sending it back to NH DHHS.
  • If your healthcare provider has access to the NHIIS, ask him/her to print out the record directly from NHIIS.

My vaccination is not recorded properly in the NH DHHS database. I have a vaccination card, but some travel destination require the full record. What should I do?

Contact NHIIS (NH Immunization Information System) at 603-271-4028, by email at click here for the  NH DHHS website for the immunization information system (NHIS). On this site, you will be guided in selecting the correction forms for your PCP to verify your vaccine card, DOB, etc. You will need to get the form notarized and before sending it back to NHIIS. Once your record is corrected and you can request an official vaccine and immunization record. This record is the one that would be accepted when travelling if the vaccine card is not enough.



    How effective will my vaccination be against COVID-19 variants?

    There is some evidence to suggest that antibodies generated through vaccination with currently authorized vaccines will recognize these variants. This is being further investigated and more studies are underway. Studies of the Moderna and Pfizer vaccines (whose early trials were largely completed before the variants emerged) include small modifications intended to enhance their effectiveness against new variants. The Johnson & Johnson trial that occurred later in the pandemic and was tested in South Africa where one of the variants emerged, still demonstrated high effectiveness in preventing hospitalization and death, although it was slightly less effective in preventing infection. The continued transmission of the variants, especially the B.1.1.7 (UK) variant, makes taking continued precautions like masking prudent, especially if you will be indoors and unable to properly distance.  Outdoors is safer than indoors for reducing your risk of infection. (Source: Journal of Infectious Diseases, Outdoor Transmission of SARS-CoV-2 and Other Respiratory Viruses: A Systematic Review) 

    For CDC information about the variants, click here.  For details regarding their spread, state by state, click here.

    What should I do if I’m exposed to someone who tests positive for COVID-19?

    Once fully vaccinated, you do not need to quarantine if you are exposed to someone with COVID-19, according to guidance from the Centers for Disease Control and Prevention.

    However, you should monitor yourself for COVID-19 symptoms for 14 days after any exposure and if you become symptomatic, contact your health care provider and schedule a COVID-19 test.


    Once I’m fully vaccinated can I hug someone who is not vaccinated?

    It should be relatively safe for you to hug an unvaccinated person who is at low risk for COVID-19. But consider wearing a mask and be sure to wash your hands or use hand sanitizer before getting close.

    Can I care for someone with COVID-19?

    While getting the COVID-19 vaccine may help keep caregivers from getting seriously ill, it might still be possible to be infected when exposed to the virus. If you are caring for someone with COVID-19 at home, you should do what you can to protect yourself and others to minimize transmission of the disease: limit contact, eat in separate areas, avoid sharing personal items, wear a mask and gloves, wash hands frequently and self-monitor for any symptoms of infection. 

    How about indoor dining?

    Outdoor dining in an open environment with lots of ventilation is safer than dining indoors. Since COVID-19 is spread via airborne particles, being indoors without a mask and near others who are unmasked while eating presents an opportunity for the virus to spread.

    If you choose to dine indoors be sure to wear a mask when entering and leaving the restaurant, when leaving your table for any reason, and when you are not actively eating or drinking.  This is especially important if you are in a high-risk category for illness from COVID-19.

    Outdoor dining in a semi-enclosed environment (such as a dome or igloo with open doors and windows) – even with only your household members --  is not as safe as a fully-open outdoor setting.  Most restaurant protocols limit gatherings in semi-enclosed settings to immediate household.

    What about travel?

    The CDC guidance and NH DHHS guidelines continue to urge caution while traveling, whether or not you are fully vaccinated, for example:

    • Fully vaccinated people should continue to take COVID-19 precautions while traveling internationally.
    • Masks are required on planes, buses, trains, and other forms of public transportation traveling into, within, or out of the United States and in U.S. transportation hubs such as airports and stations.
    • Fully vaccinated people must still have a negative COVID-19 test result before they board a flight to the United States and get a COVID-19 test 3 to 5 days after returning from international travel.

    However, some other requirements have been modified for fully vaccinated travelers, for example:

    • Fully vaccinated travelers do not need to self-quarantine in the United States following international travel
    • Fully vaccinated people do not need to self-quarantine after returning to the United States, unless required by a state or local jurisdiction.
    • The CDC and US State Department revised their international travel guidance on June 14, 2021 and moved 58 countries and territories out of the "Do Not Travel" (Level 4) category. CDC advises that unvaccinated citizens should avoid nonessential travel to the Level 3 "Reconsider Travel" category and that those who do decide to travel to those countries should be vaccinated. Canada and Mexico are in the Level 3 category. Note: On June 11, 2021, Prime Minister Trudeau ended the requirement that Canadians returning from visits to the US must quarantine for 2 weeks.

    Always check for additional requirements that may apply at your destination.

    State, local, and territorial governments may have travel restrictions in place, including testing requirements, stay-at-home orders, and quarantine requirements upon arrival. For up-to-date information and travel guidance, check the state or territorial and local health department where you are, along your route, and where you are going. Prepare to be flexible during your trip as restrictions and policies may change during your travel. Follow all state, local, and territorial travel restrictions.

    The risk of infection, even following vaccination, is higher in public spaces. Although planes have better air filtration, the risk is high in enclosed public transportation modes such as buses, trains, subways, rideshares as these transportation modes are poorly ventilated.  Continue to wear a mask, distance and wash your hands frequently.

    What about the gym?

    Two studies done over the summer identify the high risk of going to a gym and exercising without a mask, in proximity to others, in poorly ventilated spaces.  Given the high rate of heavy exhalation it is recommended that if you choose to return to the gym after full vaccination that you wear a well fitted mask and socially distance.  Try to find a workout spot near an open door or window and limit your time.

    How about a hair salon or barber?

    NH has eased restrictions on barbers and salons. Once you are fully vaccinated it is much safer to head into a salon or barbershop. The staff – and other patrons -- should be wearing masks. If you can wear a mask even part of the time, you will reduce your risk of becoming infected.

    How about visiting the dentist?

    It is riskier for the dentist than it is for you.  Dentists were in the first group in NH to receive vaccinations; check to see if the staff in the dental office is vaccinated.  Even before the pandemic most dentists and dental staff wore masks, face shields and gloves, and practiced frequent handwashing.

    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 research data is collected, there will be better guidance on the need for additional shots.