Vaccine FAQs

Latest Update from Our Experts, December 20, 2021

The ongoing vaccine campaign against Covid-19 has been an amazing success story. The vaccines were initially shown to be highly effective in the first studies, and later studies looking at their effectiveness with widespread use has further confirmed that these vaccines are highly effective. In addition, the vaccines have been shown to be extremely safe with most side effects being mild or moderate and lasting days at most. Like any medical therapy, there have been reports of more severe reactions, but they have fortunately been rare. Finally, the vaccine has been distributed at a faster pace than many hoped. At this point, over 200 million people have been fully vaccinated in the USA alone (nearly 500 million doses administered) with all available evidence showing the vaccines are safe and effective.

Vaccine distribution has greatly improved. At this time the local health department as well as local hospitals, pharmacies, and other sites all have vaccine available. Finally, specifically for the Pfizer vaccine, it has been approved for people as young as age 5 making it possible to vaccinate a larger portion of the population to help further stamp out transmission of this virus.


Frequently Asked Questions about the COVID-19 Vaccine:

Three vaccines have been licensed, one by Pfizer, one by Moderna, and one by Johnson and Johnson. The Pfizer and Moderna vaccines are a two-dose series spaced weeks apart (three weeks apart for Pfizer and four weeks apart for Moderna). The Johnson and Johnson vaccine is a one-dose vaccine.

The data shows the vaccines are extremely effective. In all cases, some degree of efficacy was seen as early as 10-14 days after the first vaccine dose.

The Moderna vaccine initially looked at approximately 29,000 individuals evenly split between vaccine and placebo groups and in the placebo group there were a total of 269 cases of Covid-19 compared to only 19 in the vaccine arm (estimated efficacy of 94.1%). The efficacy did appear lower in those over age 65 (86.4%).

The Pfizer vaccine looked at approximately 37000 individuals evenly split between vaccine and placebo groups and in the placebo group there was a total of 172 cases of Covid-19 compared to only 9 in the vaccine arm (94.8%; specifically looking at time frame >7 days after dose two). The efficacy appeared to be similar in those age >65 (94.7%).

The Johnson and Johnson vaccine looked at approximately 39,000 individuals again split between vaccine and placebo groups. This vaccine is different in that it only requires a single dose, and the effectiveness of the protection increases over a period of weeks. When looking at the effectiveness overall from 28 days after the dose of the vaccine, the effectiveness was 65.5% against moderate to severe disease and 83.5% against severe to critical disease.

Over time more data has become available. Looking at large population studies in Israel looking at 6.5 million people showed that vaccinated individuals the effectiveness was 92% again documented infection, 97% against symptomatic infection, and 97% effective against hospitalization or death.

More recent data looking at the Delta variant has shown that the vaccines appear to be less effective against any symptomatic disease. However in all studies the vaccines have remained incredibly effective at preventing hospitalization or death.

It cannot be stressed enough that nearly all deaths from Covid are occurring among those who are not vaccinated. The vaccine is extremely effective at preventing severe infection, hospitalization, or death.

To date, the safety profile of the vaccines seems to be very comparable to other vaccines. The Moderna vaccine had local pain, fatigue, and myalgia/arthralgia as the most common side effects with most being mild to moderate. Chills were common after the second dose as well. The Pfizer vaccine is similar with local pain, fatigue, headache, and fever all being reported. The Johnson and Johnson vaccine was similar with local pain, swelling, and redness near the injection site as well as headache, fatigue, and body aches all being reported and all being mild to moderate in nature.

In regards to more severe side effects they have occurred but they are rare. For example the Johnson and Johnson vaccine has been associated with episodes of low platelet and blood clots however as of May 7, 2021 there were a total of 28 reported cases out of 8.7 million doses. Cases of myocarditis after the mRNA vaccines (Pfizer and Moderna) have also been reported but again the estimated rate for men under the age of 30 was 41 cases per million vaccinated (the risk of getting  myocarditis from Covid itself is likely higher). Finally there have been reports of Guilliain-Barre Syndrome after receiving the Johnson and Johnson vaccine however the most recently available numbers show only 100 preliminary reports of GBS out of 12.5 million doses of the vaccine.

Cases of anaphylaxis have been reported. The incidence of anaphylaxis appears to be very low on the order of 2-5 cases per million doses of vaccine. At this time hundreds of millions of doses have been given without any pattern of anything other than rare reactions occurring.

Without question the danger from the virus is higher than the danger from any of these vaccines.

For some time, the Pfizer vaccine has been approved for use in children as young as age 12 (the original study included patients as young as age 16 of note). Side effects in pediatrics were very similar to adults, except pain at the injection site was more commonly reported (up to 86% reporting pain after the first dose and 79% after the second dose) as well as fatigue, headache, muscle pain, and chills all being commonly reported though all noting mild to moderate severity. Lymphadenopathy following vaccination was seen as well.

Recently specifically the Pfizer vaccine was approved for the age group of 5 – 11. The vaccine dose for children ages 5-11 is lower than those ages 12 and up (and uses a smaller needle). Children do require a second dose three weeks after the first same as older children and adults. Vaccination can protect children against illness including short-term and long-term effects. In addition, overall those who are vaccinated are less likely to spread the virus then those who are not. While no medical treatment is 100% safe after hundreds of millions of doses given the safety profile of the vaccine has been excellent and without question the vaccine is far safer than the virus itself. Rare allergic reactions have occurred (<5 cases per million doses) and rare cases of myocarditis (around 54 cases per million doses for males age 12-17) have been seen with cases of myocarditis typically being mild and responding to therapy. The vaccine cannot cause Covid-19 as the vaccine does not contain any living or active virus.

Prior to vaccination (from

  • Talk to your child before vaccination about what to expect.
  • It is not recommended you give pain relievers before vaccination to try to prevent side effects.
  • Tell the doctor or nurse about any allergies your child may have.
  • To prevent fainting and injuries related to fainting, your child should be seated or lying down during vaccination and for 15 minutes after the vaccine is given.
  • After your child’s COVID-19 vaccination, you will be asked to stay for 15–30 minutes so your child can be observed in case they have a severe allergic reaction and need immediate treatment. 

At this time we would recommend vaccination for children to protect both them and their families from this dangerous virus.

As above the data strongly suggests it is highly protective, lowering chance of Covid 19 infection by up to 95% in some studies with even greater protection against severe disease.

The short answer is that all available information shows that being vaccinated greatly reduces the risk for someone to transmit the virus.

Vaccinated individuals appear to often have lower amounts of the virus present during infection and more rapidly clear the virus giving a decreased odds and shorter window of odds to spread the virus.

It is not realistic to expect that the vaccine is 100% effective at preventing the spread of the virus and other means of risk reduction still have an important role particularly for more vulnerable patients (such as those on immune suppressive medications for example) including physical distancing and mask wearing.

In many specific instances being vaccinated means that a mask is no longer necessary. For example, two healthy adults who have both been vaccinated and do not have any symptoms nor any recent exposure to a known case of Covid would not need to wear a mask when visiting together.

Situations where a mask definitely should still be worn include (but not limited to); during travel, at healthcare facilities, when interacting with high-risk individuals (again such as those on immune suppressive medications), and when still required by local/state/federal guidelines.

In addition, with the rapid spread of the Delta variant would strongly recommend continued use of mask wearing while in public places, particularly in areas with high levels of community transmission of the virus and low levels of vaccination.

For the Pfizer vaccine, the CDC has approved vaccinations for patients ages 12 and up. Please note: At Wilmington Health, a parent or guardian must be present for any patient 18 or younger receiving a vaccination.

All other vaccine manufacturers are approved for any adult aged 18 or older.

At this time, that is not known. The vaccines were developed and studied initially in late 2020 into early 2021 so the follow up period has only been since that time. Monitoring is ongoing to determine how long immunity lasts.

Pfizer vaccine:
Patients 12 and older now qualify for Pfizer, and they qualify for a booster 5 months after the second dose.

Moderna vaccine:
You should get the booster dose six months after the last dose if you are 18 years or older

Johnson & Johnson vaccine:
You should get a booster two months after the last dose if you are 18 years or older.

The vaccine delivers a strand of mRNA which then encodes the spike protein. The body then develops an antibody response to this protein and the mRNA strand is degraded as typical for any mRNA fragment. The mechanism brings up several points:

  1. This is not a live vaccine and as noted above even patients with underlying malignancy and HIV were included
  2. mRNA does not incorporate itself into the host genome

Currently three vaccines are available. The Pfizer and Moderna vaccines are both based on mRNA technology. The vaccine by Johnson and Johnson is based on a different technology. At this time, it does not appear there is any compelling reason to choose one over the other for most patients. Would recommend speaking with your doctor about the different options. It remains possible that other vaccine options will be available in the future.

As above there have been reports of issues with blood clots with the Johnson and Johnson vaccine. The numbers were very small, and the rate appears to be around 1 episode per 140,000 doses with cases being seen in women under the age of 50 and above. For those patients, some doctors may advise women under the age of 50 to have one of the two mRNA vaccines that are currently available.

As above, specific data on subgroups is limited but ACOG and other experts all agree the vaccine should not be withheld based on pregnancy or breastfeeding status.

As above would recommend, speak with your doctor or OB prior to vaccination. Pregnancy itself is a risk factor for severe Covid, which should be considered when making the decision to get vaccinated. Would recommend to any woman who is pregnant or breastfeeding to get vaccinated to protect themselves and their family.

While the data is limited, there is no evidence to suggest danger in vaccinating those who previously had Covid-19 infection. Given the duration of immunity after infection is not known, we would not use previous Covid-19 infection as a reason to withhold vaccination. Would recommend anyone who previously had Covid to also get vaccinated.

In theory, antibody testing could be used to determine if a patient previously had a Covid infection, if they are potentially immune, or to monitor response to vaccination. In practice, the data on antibody testing remains limited and in particular the long-term data on antibody testing is not known. At this time, we would recommend against using antibody test results as a factor in determining whether or not to vaccinate a patient.

Likely, right now! Obtaining the vaccine is far easier than it was even two months ago. Many sites such as the local department of health, hospitals, and several pharmacy chains all have supplies of the vaccine. The following website has frequently updated information for those in North Carolina looking to get vaccinated.

The short answer remains absolutely yes. There does not appear to be any other way out of the current pandemic other than widespread vaccination. The Covid-19 pandemic is easily the worst in the past century and given the amount of societal harm and death that has already occurred compared to the level of safety for the vaccines seen in large clinical trials the answer should be an easy yes.

  1. The data on vaccine effectiveness remains very encouraging particularly for severe disease or death
  2. The ongoing safety data remains favorable with severe adverse events being very rare even after hundreds of millions of doses
  3. While there are many questions about the vaccine the mechanism of action does not raise the same concerns as a live attenuated vaccine (note that the Johnson & Johnson vaccine uses an adenovirus vector that has been modified to prevent replication – again it is not a live virus vector)
  4. The pandemic is still causing tremendous harm and these vaccines are necessary tools to end it
  5. In almost all cases getting vaccinated is the right answer. It is highly unlikely that we will successfully manage this pandemic without ongoing mask use, social distancing, hand washing, and arguably most important – vaccination.

Again, yes. The duration of immunity after infection is unknown. Any additional protection against the virus is helpful in stopping this deadly pandemic.

The optimal timeframe is not known. There is strong evidence that an individual who has Covid is immune for at least 90 days with growing evidence that time could be as long as six months. As more data is gathered, it would not be surprising to see that time-frame increase. Currently CDC recommendations state it is reasonable to wait 90 days after having Covid. It is likely very reasonable to have the vaccine series anytime 3-6 months after having Covid. This recommendation may well change with new information being available.

Yes, the recommendation would still be to have the second dose. It should not be given any sooner than recommended (time between doses being three weeks for Pfizer and four weeks for Moderna). In addition, an individual should wait until they are out of quarantine and no longer contagious before having the second dose even if this means delaying the second dose (i.e., an individual should wait until the appropriate three- or four-week period has passed and until they are no longer contagious – whichever is longer).

 “The goal of the first vaccine is to “prime” the immune response; the second “boosts” it. Although most participants in the trials received their second dose on or close to the scheduled time, there is no biological reason why receiving the second dose late would diminish the effectiveness of the vaccine, provided it is received before too long an interval. In practice, the second dose should be given as soon as possible after the missed scheduled dose. 

On January 21, 2021, the CDC updated its guidance on the interval between vaccine doses, providing additional information on delayed dosing. Specifically, the agency says that when the recommended schedule is not feasible, the second dose may be scheduled for administration up to 6 weeks (42 days) after the first dose. Although there are currently limited data on the efficacy of mRNA Covid-19 vaccines administered beyond this window, if the second is given later than this, the series still does not need to be restarted. (Last reviewed/updated on 16 Mar 2021)”.


For up-to-date information regarding COVID-19 in North Carolina, as well as information on vaccines, please visit: