Pfizer and Moderna COVID-19 vaccine booster shots are available to individuals who received the Johnson & Johnson vaccine at least two months ago or the Moderna or Pfizer-BioNTech vaccine at least five months ago. COVID-19 vaccine recipients are able to receive any one of the approved vaccines as boosters, regardless of the vaccine brand they received previously. Youth over the age 12 are eligible to receive a booster dose of the Pfizer vaccine five months after receiving the second dose of the Pfizer vaccine. The CDC is recommending booster shots for all individuals ages 12 and older. This is because there is increasing evidence that COVID-19 antibodies produced by the immune system decrease significantly after 5 months. Note that antibodies are not the only lines of defense that are triggered by the vaccines. There are other components of your immune system, such as memory cells and killer cells, that help defend your body from an infection and are part of the response to the vaccine. For more information, please visit the DOHMH's website.

The best advice for this group of people is to get vaccinated as soon as possible. Vaccines will protect you from getting very sick and potentially dying from COVID-19, especially if you are in a higher risk category. After you are fully vaccinated, then the consistent use of facial coverings in all indoor spaces, and crowded outdoor gatherings is strongly recommended. Strict use of facial masks is also recommended when using public transportation, in addition to frequent hand hygiene. If you do have any underlying conditions that make you more susceptible to an infection, it is still advisable to avoid indoor crowds whenever possible, and to limit close contact with any group whose vaccine status is unknown.

There are no safety concerns for getting tested weekly. Not all tests use a nasal or oral swab, there are some tests that use a sample of saliva to test for COVID-19.

In addition, there are rapid antigen tests that can be purchased (but you can be reimbursed by insurance) Rapid antigen testing is a faster way to detect if you have a current COVID-19 infection. Most tests use a nasal or throat swab. Results are typically ready in just 15 to 30 minutes.  However, they may not be as accurate as a PCR test, especially for people who do not have symptoms.  To fully protect yourself and your loved ones, specifically those with underlying conditions and those who are not yet eligible for a COVID-19 vaccine (i.e., younger children), the best choice is to receive a vaccine.

Many of you asked me whether the COVID-19 vaccine was safe, which is a reasonable and important question to ask! You'll be happy to know that I can answer each of you in just one word: yes!

For those of you who want more information, I can assure you that all vaccines currently used in the United States are incredibly safe and effective and have undergone extensive scientific testing on tens of thousands of people, before they are approved, including the COVID-19 vaccine. In fact, researchers have been working on vaccines for coronaviruses for years, so they did not start from scratch. You should know that the vaccine does not contain the COVID-19 virus; it teaches your body's immune system how to fight the COVID-19 virus so that your body can aggressively fight back if you're exposed.

This is another common question. Common side effects include: soreness in the arm where you got the shot, headache, body aches, tiredness and low-grade fever. The CDC and the FDA continue to monitor for any adverse reactions and so far, the only serious safety concerns relate to very rare allergic reactions which have occurred in about 1 per 100,000 vaccine recipients. If you have any questions or concerns, you should speak directly with your health care provider. As a reminder, side effects can be unpleasant, but getting vaccinated helps protect you from the COVID-19 virus.

Yes. Since it is possible to get COVID-19 again, you should still get vaccinated. Also, the vaccine is safe and may boost the protection your body has already built up. People currently infected with COVID should get vaccinated as soon as they have recovered from the acute illness (if symptoms were present) or if they have completed isolation. You no longer have to wait 90 days to be vaccinated unless you were taking monoclonal antibodies as treatment for COVID infection.  As always, you should speak directly to your health care provider if you have questions.

No, it doesn't matter which vaccine you receive. The Pfizer and Moderna vaccines are both mRNA vaccines, meaning no part of the actual virus is injected. mRNA vaccines teach our cells to produce a protein similar to a protein in the virus. This protein then results in an immune response so that the body knows how to fight the virus if it is later exposed to the actual virus. In clinical trials, both the Pfizer and Moderna vaccines were shown to be safe and effective at preventing symptoms and decreasing severe COVID-19 infection among study volunteers. The Pfizer and Moderna vaccines each require two doses, through shots in the arm, at least 21 days (Pfizer) or 28 days (Moderna) apart.

Since we do not know how long the antibodies last after recovery from a COVID infection, the CDC still advises that even those who have had a previous infection should still receive the COVID vaccine. Based on the clinical trials, the 2 mRNA vaccines have consistently resulted in an immune response that leads to at least a 94% protection, something we cannot predict will happen after an infection.

Right now, the CDC is stating that you can still take the second dose up to 6 weeks after the first dose. Theoretically, it shouldn't matter if there is a delay in getting the second dose by a few weeks, however, the Clinical Trials did not test for such a situation. If and when possible, I would suggest getting the second dose within the suggested timeframe.

It's not required that you get approval from your medical provider; however, it is always a good idea to consult with your doctor - especially if you have any medical concern, long-standing medical diagnoses, or are receiving treatment for an ongoing medical condition.

The vaccine does not generally have negative effects on those with underlying conditions. In fact, it can protect those with underlying conditions from experiencing severe symptoms if infected with the SARS CoV-2 virus, the virus that causes COVID-19. Even those with histories of allergies may receive the vaccine, as long as they do not have an allergy to any component of the vaccine itself. Please consult your doctor if you have any underlying conditions, or if you are not sure about your allergies, before receiving the vaccine.

Currently, the minimum age to get the COVID-19 vaccine is 5. The Pfizer vaccine is approved for individuals for Emergency Use Authorization (EUA) for individuals aged 5-16 years and is fully approved for individuals 16 years and older. The Moderna and Johnson & Johnson vaccines are approved for those 18 years old and above. Studies are currently being conducted on vaccines for children under 5 years of age, but it is unclear when we will have the results and when these vaccines will be approved for use. It is, therefore, very important that as many eligible adults get vaccinated as soon as possible to avoid transmission to children who are not yet eligible for vaccination.

The night before the vaccine appointment, get a full night's sleep and eat a nice dinner. On the day of the vaccine, make sure to drink lots of fluids, get some rest, and if you experience pain or fever, you can take some regular Tylenol (not ibuprofen). Remember that if you are taking any medications to manage the after-effects, you should take those medications after you receive the vaccine, not before.

We do not yet know how long the vaccines will protect people from COVID-19. Studies continue to be conducted, but at this time protective immunity is being shown to last up to 6 months after completing the vaccine series (2 weeks after the second dose of any of the mRNA vaccines and 2 weeks after the single J & J vaccine). This is based on our experience from the clinical trials and from the time the vaccine was made available to the public.

It may be that a vaccine is needed annually (like a flu shot) or that additional booster shots will be needed (like with a tetanus shot). Continued research and time will tell us how long the vaccines' protection last and whether additional doses are needed. People who participated in the clinical trials will continue to be monitored and we will learn more over time from the millions of people being vaccinated in the U.S. and around the world. We will share information about this as soon as we know.

It has not yet been determined whether annual COVID-19 vaccines would be necessary in the future. One of the predictors for the need for annual vaccinations is the number of SARS CoV-2 variants and the speed in which they emerge. The best way to slow down the emergence of new variants is by vaccinating as many people as possible, as soon as possible. We continue to monitor the pandemic and the effects of the vaccines in controlling the spread of disease. It is still a possibility additional shots will be needed and we will share information about this as soon as we know.

There is no evidence that having had COVID-19 will cause a person to have a bad reaction to the vaccines. Most people report some side effects from the vaccines, which are usually signs that the body is building protection. Common side effects include soreness or swelling on the arm where you got the shot, headache, body aches, fatigue and fever. For the Pfizer and Moderna vaccines, you should get the second shot even if you have side effects after the first shot, unless your health care provider tells you not to do so. Side effects:

• Usually are mild to moderate;
• Usually start within the first three days after vaccination (the day after vaccination is the most common) and last for about one to two days after they begin;
• Are less common in older adults; and
• Are more common after getting the second dose or booster dose of the Pfizer or Moderna vaccines than after getting the first dose

All three vaccines are very safe and effective at preventing severe illness, hospitalization and death. The most important thing is to get vaccinated, with whatever vaccine is available to you, since the best vaccine is the one that you can get! Both the Pfizer and Moderna vaccines require two doses. The Johnson & Johnson vaccine is just one dose at this time. However, booster doses are recommended for adults who have received any of the three vaccines. All three vaccines cause similar mild to moderate side effects.

It is hard to directly compare the vaccines effectiveness since they were tested at different times and in different locations. Johnson & Johnson trials were conducted more recently, when there were higher levels of COVID-19 transmission, and in countries that have high levels of the new variants. Even under these circumstances, the vaccine effectively prevented hospitalizations and deaths.

A key difference among the vaccines is that only the Pfizer vaccine is authorized for people under the age of 18. The Moderna and Johnson & Johnson vaccines are authorized for people ages 18 and older. Another difference is how the vaccines can be stored and distributed. The Johnson & Johnson vaccine is more stable and can be kept in a refrigerator, making it easier to transport and reach people who cannot travel to a vaccination site. For now, most vaccination sites have only one type of vaccine. The type of vaccine you get will depend on where you go. The NYC Vaccine Finder shows the type of vaccine given at each site.

The Johnson and Johnson vaccine has been shown to have 85% efficacy rate in preventing severe COVID-19 illness across clinical trial populations in different regions. Overall efficacy against lab-confirmed, symptomatic COVID disease was 66.3% and efficacy against hospitalization is 93%.

It is difficult to compare efficacy of the Johnson & Johnson vaccine against the mRNA vaccines because the trials were not done in the same geographic locations. They were also done during a different time. These can affect the results because the infection rates and predominant variants vary according to time and location, thus affecting efficacy rates as well.

I strongly recommend the Johnson & Johnson vaccine with the same enthusiasm as I have recommended the mRNA vaccines. Since we are still dealing with limited supplies and the COVID pandemic continues to cause unprecedented deaths, the best vaccine is the one that is available to you!

No, it does not mean that. Reactions vary individually but common side effects are soreness/swelling on the arm where you got the shot, headache, body aches, tiredness and fever. Side effects are more common after the second dose and booster dose and less common in older adults, but it does not mean that older adults are less protected against COVID after being vaccinated.

Yes, you can still get infected between doses of the mRNA vaccines. You will not have full (94-95%) protection from the vaccine until one to two weeks after your second dose. It is always important to continue to practice prevention measures: stay at least 6 feet from others, wear your proper-fitting face covering, and wash your hands often.

Typically, when making an appointment, the website will tell you which vaccine is being administered at that site. However, please remember that all three vaccines are very safe and effective at preventing severe illness, hospitalization and death. The most important thing is to get vaccinated, with whatever vaccine is available to you. Bottom line - the best vaccine is the one that you can get!

All vaccines have side effects, and these are not unique to the COVID-19 vaccine. Side effects indicate that the vaccine is strengthening your body's immune response, which is the goal of all vaccines. The night before the vaccine appointment, get a full night's sleep and eat a healthy dinner. On the day of the vaccine, make sure to drink lots of fluids, get some rest, and if you experience pain or fever, you can take some regular Tylenol. Remember that if you are taking any medications to manage the after-effects, you should take those medications after you receive the vaccine, not before. To reduce pain and discomfort where you got the shot, you can also apply a clean, cool, wet washcloth over the area.

Common side effects are mild and consist of: soreness or swelling on the arm where you got the shot, headache, body aches, tiredness and fever. Side effects are more common after the second dose and less common in older adults. Side effects usually are mild to moderate, start within the first three days after vaccination (the day after vaccination is the most common), and last about one to two days after they begin. Call your health care provider if you have any side effects that concern you or do not go away after a few days, or if the redness or soreness where you got the shot increases after 24 hours.

As noted above, vaccine side effects are usually mild-moderate and only last for a few days. They mimic the initial symptoms of an infection (e.g., fever, headache, body aches) which are the result of an immune system that is actively fighting the cause of the infection. Vaccines work by preparing your immune system to fight disease by creating antibodies and by training other immunity-enhancing cells to recognize and neutralize germs such as viruses and bacteria. The more prepared and trained your immune system is, the more pronounced these symptoms may become.

It is, therefore, reasonable to expect that people who have had a COVID-19 infection may have more prominent symptoms because their immune response will be more intense. This is also the reason behind more reports of side effects after the second dose of either the Pfizer or Moderna vaccine. Even so, these vaccine-related symptoms cannot be compared to the severity and duration of symptoms from a COVID-19 infection and the potential complications which may even lead to death.

Currently, the Pfizer vaccine can be administered to young people 5 years and older.  Clinical trials for younger children are ongoing.

That's great that you are interested in donating blood! The vaccine does not affect the ability to donate blood at any time after it is received. This is true for the vaccines currently available in the US. If you've received a COVID-19 vaccine, you'll need to provide the manufacturer name when you come to donate. In most cases, there is no deferral time for individuals who received a COVID-19 vaccine as long as they are symptom-free and feeling well at the time of donation. If you experience any side effects from the vaccine, it would be best to wait until those symptoms have resolved.

Also, blood donations will not affect the efficacy of the vaccine for someone who is vaccinated, no matter how close or remote to the time during which the vaccine is received. It will be best to donate blood 14 days after the second dose of a mRNA vaccine (Pfizer or Moderna) or the single dose of the Johnson & Johnson (Janssen) vaccine, so you are fully protected in case you are exposed while at the blood donation facility. Please continue to volunteer for blood donations, as times like these often result in shortages of life-saving supply.

An allergy to any component or ingredient of the COVID vaccines and a previous severe adverse reaction to the COVID vaccine are the only contraindications to receiving the vaccine. All other allergies of any kind (asthma, food allergies, environmental allergies to dust or pollen) do not exclude you from the vaccine. In fact, those with asthma are at high risk for developing fatal complications, even death, from a COVID-19 infection. Only you, with the advice of your doctor, can determine whether you are allergic to a component of any of the vaccines.

Yes, a study in Massachusetts demonstrated that the COVID-19 vaccines confer protective immunity to newborns through breast milk and the placenta. Of course, this is quite good news for pregnant and lactating women. The side effects after vaccination were rare and comparable across the study participants. In addition, a comparison of antibody responses showed higher antibody levels after vaccination compared to levels after a COVID-19 infection.

CDC recommends COVID-19 vaccination for women who are pregnant, recently pregnant, who are trying to become pregnant now, or who might become pregnant in the future. Since the CDC states that pregnant women are more likely to suffer severe complications from a COVID-19 infection and may be at increased risk for adverse pregnancy outcomes, this study further supports the importance of vaccinating pregnant women, and women who may become pregnant. The vaccine may not only save the pregnant individual's life, it may also be life-saving for the infant, knowing that the vaccine is not yet approved for use in young children.

Most people who have COVID-19 completely recover, but some have lasting symptoms and health problems. These people sometimes describe themselves as "long haulers" and the condition has been called post-COVID-19 syndrome or "long COVID-19."

Some people who have spent months suffering from long-haul COVID-19 are reporting their symptoms disappearing after their vaccinations, leaving experts chasing yet another puzzling clinical development surrounding the disease caused by SARS CoV-2.

One small study not yet submitted for peer review concluded that people with long-term symptoms who get vaccinated are more likely to see their problems resolve or not worsen than people who have not been vaccinated. Several theories have emerged, although researchers have barely begun to explore them. One theory is that the coronavirus vaccine could be triggering an immune response sufficient to eliminate any viral holdouts. More studies are needed to know for sure.

The potentially long-lasting problems from COVID-19 make it even more important to reduce the spread of the disease by following precautions such as wearing masks, avoiding crowds, postponing travel, keeping hands clean and getting vaccinated!

More information on Post-Acute COVID-19 Syndrome

Infertility has not been found to be a problem in women who have had COVID-19, so it would not be expected to be an issue for the vaccine. Furthermore, the vaccines do not contain the SARS CoV-2 virus or any part of the virus. People who are trying to become pregnant now or who plan to try in the future can be vaccinated. Vaccines are monitored and tested closely before being authorized for use and afterwards, while it is being administered to the public. There is no evidence that fertility problems are a side effect of COVID-19 vaccines, or of any other vaccines.

Claims of infertility are based on a misunderstanding of the science. The COVID-19 vaccines, like many other vaccines, work by teaching our body to create antibodies to fight the virus. Concerns of infertility are based on the idea that the antibodies will attack a protein in the placenta that has a few things in common with a protein found in the COVID-19 virus. However, the two proteins are very different, and our immune systems are smart enough to tell the difference. There is currently no evidence that these antibodies will cause any problems in pregnancy, including development of the placenta.

It is the same dose and formulation for each shot of the same vaccine, including the booster dose. The Moderna vaccine has a slightly higher dose than the Pfizer vaccine. As a reminder, both doses should be of the same vaccine but regardless of which vaccine you received during your two-dose series, you may receive a booster dose of either Pfizer, Moderna or the Johnson and Johnson vaccine. But the Pfizer-BioNTech or Moderna (COVID-19 mRNA vaccines) are preferred boosters by the CDC.

If you already received the vaccine, it may be helpful to speak about your experience with your friends and family members who are hesitant. You can speak about why it was important for you to get the vaccine, whether you experienced any side effects, and how you managed these side effects. Most side effects are really quite mild and cannot be compared to the risk of complications from a COVID-19 infection, which can include death. You might also want to ask your friends and family about why they are hesitant, and then share factual information that might address their concerns. Many family members actually do trust other family members, especially if they are speaking from experience. Please let your loved ones know that getting the vaccine is the best way you can protect each other, especially those who are too young to receive the vaccine at this time. The highest increase in new cases in recent weeks has been from younger populations. Of course, always make sure to share information from reliable sources, like the DOHMH website or even the Ask Dr. Mendoza columns!

Two doses provide more protection than just one dose. One dose of a 2-dose vaccine will only give you between 50 to 80 percent protection from severe disease, as opposed to close to 100% with complete vaccination. Why settle for lower efficacy after a single dose when, after 2 doses, you will be more protected from severe disease and possibly, death from a COVID-19 infection?

As of the week of 1/19/2022, approximately 82 percent of New York City's population has received at least one dose of a COVID vaccine and about 73 percent are fully vaccinated. Vaccines are widely available and can be administered on a walk-in basis at most sites.

Viruses constantly change through mutation, resulting in new variants of a virus. Multiple variants of the virus that causes COVID-19 have been documented during the pandemic. By carefully studying viruses and their variants, scientists can learn how changes to the virus might affect how it spreads and how severe the symptoms of an infection can be.

Mutations in viruses - including the coronavirus causing the COVID-19 pandemic - are neither new nor unexpected. All RNA viruses mutate over time, some more than others. For example, flu viruses change often, which is why doctors recommend that you get a new flu vaccine every year. Some variations allow the virus to spread more easily or may make it resistant to treatments or vaccines. Those variants must be monitored more carefully.

Omicron is the most widespread variant in the city.