A lot has changed since our last COVID-19 vaccine Q&A (which you can find here). So naturally, it was time for an update. You asked, we answered—here are the answers to the Immunization Ambassadors and MyIR Mobile community’s most pressing questions about the COVID-19 vaccine.

  1. How does the vaccine actually work?

According to the Centers for Disease Control and Prevention (CDC), the COVID-19 vaccine works in the following ways:

  • COVID-19 vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness. Different types of vaccines work in different ways to offer protection, but with all types of vaccines, the body is left with a supply of “memory” T-lymphocytes as well as B-lymphocytes that will remember how to fight that virus in the future.
  • It typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination. Therefore, it is possible that a person could be infected with the virus that causes COVID-19 just before or just after vaccination and then get sick because the vaccine did not have enough time to provide protection. 
  • Sometimes after vaccination, the process of building immunity can cause symptoms, such as a fever. These symptoms are normal and are a sign that the body is building immunity.

Types of COVID-19 Vaccines:

  • Currently, there are three types of vaccines that are authorized and recommended, or undergoing large-scale (Phase 3) clinical trials in the U.S.: mRNA vaccines, protein subunit vaccines, and vector vaccines. 
  • mRNA vaccines contain material from the virus that causes COVID-19 that gives our cells instructions for how to make a harmless protein that is unique to the virus. After our cells make copies of the protein, they destroy the genetic material from the vaccine. Our bodies recognize that the protein should not be there and build T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes COVID-19 if we are infected in the future.
  • Protein subunit vaccines include harmless pieces (proteins) of the virus that causes COVID-19 instead of the entire germ. Once vaccinated, our bodies recognize that the protein should not be there and build T-lymphocytes and antibodies that will remember how to fight the virus that causes COVID-19 if we are infected in the future.
  • Vector vaccines contain a modified version of a different virus than the one that causes COVID-19. Inside the shell of the modified virus, there is material from the virus that causes COVID-19. This is called a “viral vector.” Once the viral vector is inside our cells, the genetic material gives cells instructions to make a protein that is unique to the virus that causes COVID-19. Using these instructions, our cells make copies of the protein. This prompts our bodies to build T-lymphocytes and B-lymphocytes that will remember how to fight that virus if we are infected in the future.
  1. Do current COVID-19 vaccines protect against new variants of the virus that causes COVID-19? 

Viruses in general constantly change through mutation, and new variants of viruses are expected to occur over time. 

As of this writing, five known variants of SARS-CoV-2 (the virus that causes COVID-19) have been identified in the U.S.:

  • B.1.1.7: This variant was first identified in the U.S. in December 2020. It was initially detected in the U.K.
  • B.1.351: This variant was first identified in the U.S. at the end of January 2021. It was initially detected in South Africa in December 2020.
  • P.1: This variant was first detected in the U.S. in January 2021. P.1 was initially identified in travelers from Brazil, who were tested during routine screening at an airport in Japan, in early January.
  • B.1.427 and B.1.429: These two variants were first identified in California in February 2021 and were classified as VOCs in March 2021.

These variants appear to spread more easily and quickly than other variants. Studies suggest that currently authorized COVID-19 vaccinations recognize these variants, and the antibodies generated through these vaccines do provide some protection against the aforementioned variants—though more time is needed to study, definitively, how much protection is provided against variants of SARS-CoV-2. 

Public health officials and scientists worldwide are studying these variants in order to better understand them and better control their speed. The best way to protect yourself and your community against all variants of COVID-19 is to comply with public health mitigation strategies—like getting the COVID-19 vaccine, practicing social distancing, wearing masks, washing your hands and using hand sanitizer frequently, and quarantining and/or isolating (especially if you are sick or have come into contact with someone who has COVID-19).

  1. When can I get the vaccine? 

President Joe Biden recently set a deadline for states to make the COVID-19 vaccine available for all adults starting April 19. Prior to this, COVID-19 vaccine rollout was done in phases, under the guidance of the Advisory Committee on Immunization Practices (ACIP)—a U.S. federal advisory group made up of medical and public health experts. However, not everyone eligible for the vaccine starting April 19 will be able to get a vaccine appointment right away, due to an increased demand. The best way to secure an appointment for any one of the three COVID-19 vaccines that, as of this writing, have Emergency Use Authorization (EUA) is to check weekly—and perhaps, even daily—for appointments on your local state health department’s website. 

  1. Why do we have to get two doses of the COVID-19 vaccine? How do we keep track of this and how important is it to get the second dose on time?

Both the Pfizer and Moderna COVID-19 vaccines require two doses. Due to the way that mRNA vaccines work—including the Pfizer and Moderna vaccines in particular—it’s important to get two shots because the first shot helps your body recognize viruses such as SARS-CoV-2 (the virus that causes COVID-19) and prepares your immune system to develop an immune response, while the second shot strengthens that immune response, which in return makes your body more prepared to fight infection. It takes two weeks after your second dose of these vaccines to be fully protected. However, Johnson & Johnson Janssen’s COVID-19 vaccine only requires one shot. 

MyIR Mobile (www.myirmobile.com) is a great resource for accessing your immunization records and for vaccination scheduling. Upon receiving your first dose of any of the approved COVID-19 vaccines in the U.S., you should receive a CDC vaccination card that tells you what COVID-19 vaccination you received, the date you received it, and the date of your next shot. Most vaccine administrators schedule a time and date you should return to receive the second dose during your appointment for the first dose, if you received the Pfizer or Moderna vaccine. 

  1. Do we know how long the vaccine will be effective for?

New research has found that mRNA COVID-19 vaccines (like the Moderna and Pfizer vaccines) provide immunity for at least six months. That doesn’t mean that these vaccines only provide immunity against coronavirus for six months, it just means that not enough time has passed to know yet how much longer they may provide immunity. 

We still don’t have enough information to definitively say how long protection and immunity from the various COVID-19 vaccines that are available will last. That’s because research is ongoing for the various COVID-19 vaccines in development, as well as COVID-19 vaccines that have been granted Emergency Use Authorization (such as Johnson & Johnson, Moderna and Pfizer’s coronavirus vaccines). What we do know is that COVID-19 vaccines prevent you from getting sick with COVID-19 by teaching your immune system how to both recognize and fight SARS-CoV-2, the virus that causes COVID-19. 

Ultimately, any protection against COVID-19 is better than no protection—since there is no way to predict for sure how the illness will impact you, or someone else you may infect. Furthermore, historically, vaccines are the best and safest way to achieve herd immunity and end epidemics and pandemics (case in point: the polio and measles epidemics). It’s important to continue recommended COVID-19 pandemic best practices—washing your hands often, using hand sanitizer, social distancing and wearing masks—as it is still possible to pass COVID-19 on to others, even after developing immunity from getting both doses of the COVID-19 vaccine. 

  1. How many versions of the vaccine will there be from different companies and how will they differ?

At the time of this writing, there are currently three vaccines (Pfizer-BioNTech COVID-19 vaccine, Moderna COVID-19 vaccine and Johnson & Johnson Janssen’s COVID-19 vaccine) that have Emergency Use Authorization in the U.S. and are recommended for preventing COVID-19, as well as two other vaccines in Phase 3 clinical trials (as of April 3, 2021). However, even more COVID-19 vaccines are being developed globally. Among the coronavirus vaccines in Phase 3 in the U.S. are AstraZeneca’s COVID-19 vaccine and Novavax’s COVID-19 vaccine​. 

Both the Moderna and Pfizer COVID-19 vaccines require two doses, and work in a similar fashion, as both are mRNA vaccines. However, a key difference between the two is the recommended time in between each dose. Each dose of the Moderna vaccine should be taken 28 days apart, while the recommended time between doses for the Pfizer vaccine is 21 days. The Pfizer vaccine is also recommended for those ages 16 and up, while the Moderna vaccine is recommended for those ages 18 and up. 

Johnson & Johnson Janssen’s COVID-19 vaccine, on the other hand, only requires one dose. Currently, it’s recommended/approved for those ages 18 and over, and is a viral vector vaccine—meaning it contains a modified version of a different virus (aka vector) to deliver instructions to our cells, triggering our immune systems to produce antibodies and activating other immune cells to fight off what it believes is an infection. Although this type of coronavirus vaccine produces a harmless piece of the virus that causes COVID-19 (known as a spike protein), it cannot give you COVID-19, as it does not contain a live virus. 

  1. Are there any individuals who are advised against getting the vaccine, and who?

At the time of this writing, the Pfizer vaccine is only recommended for people ages 16 and up, while the Moderna and Johnson & Johnson vaccines are only recommended for people ages 18 and up. Testing in pregnant women and children is ongoing for COVID-19 vaccines with EUA, and studies on animals receiving the Pfizer, Moderna and Johnson & Johnson COVID-19 vaccines have shown no safety concerns during pregnancy, according to the CDC. 

Individuals with a history of allergic reactions to vaccines and/or injectable medications should discuss the risks and benefits of the COVID-19 vaccine with their doctor prior to getting the vaccine. It is not recommended for those allergic to ingredients in the COVID-19 vaccine to get it—including those who are allergic to polyethylene glycol (PEG) and polysorbate, which are in both the Pfizer and Moderna vaccines. Pregnant women who are in an authorized vaccine group should discuss with their doctor if getting the COVID-19 vaccine is the right decision for them. As with any vaccine, it’s important to discuss any allergies or medical conditions that could cause a reaction with your doctor before getting the COVID-19 vaccine. 

  1. Can pregnant women get the COVID-19 vaccine? Will it cause birth defects?

There is no evidence that approved COVID-19 vaccines cause birth defects, and mRNA vaccines are not generally considered a risk to a breastfeeding infant or lactating mother. Additionally, studies of animals who received a Moderna, Pfizer or Johnson & Johnson COVID-19 before or during pregnancy found no safety concerns. 

Based on current knowledge of mRNA vaccines, both the Pfizer and Morderna vaccines are unlikely to pose a risk to a pregnant person or fetus because mRNA vaccines are not live vaccines and degrade quickly by normal cellular processes, therefore they do not enter the nucleus of the cell. However, research is ongoing on the safety and efficacy of approved COVID-19 vaccines in pregnant women. So far, however, results have been promising, and show that when given to pregnant women, approved COVID-19 vaccines may even provide some protection against COVID-19 to the fetus. When pregnant or lactating, the CDC recommends discussing the COVID-19 vaccine with your doctor before getting the vaccine. 

  1. Do COVID-19 vaccines affect fertility in men and women? 

There is no evidence that COVID-19 vaccines can cause infertility—or affect fertility whatsoever—in men or women. However, according to the CDC, “Observational data demonstrate that pregnant people with COVID-19 have an increased risk of severe illness, including illness resulting in intensive care admission, mechanical ventilation, extracorporeal membrane oxygenation, or death, though the absolute risk for these outcomes is low. Additionally, they might be at an increased risk of adverse pregnancy outcomes, such as preeclampsia, coagulopathy, and preterm birth.”

  1. Is it possible to spread COVID-19 to others, even if I’m fully vaccinated? 

While COVID-19 vaccines provide a strong level of protection against COVID-19, the risks of SARS-CoV-2 infection in fully vaccinated people cannot be completely eliminated as long as there is continued community transmission of the virus. This is why vaccinated people could potentially still get COVID-19, as well as spread it to others. To prevent the spread of SARS-CoV-2, continue to follow CDC guidelines such as washing your hands often, social distancing, and wearing a mask in public and around those who have not been vaccinated. A more comprehensive list of precautions to take for those who have been fully vaccinated against COVID-19 can be found on the CDC’s website.  

  1. Should I get the COVID-19 vaccine if I’ve already had coronavirus? 

The CDC advises getting the COVID-19 vaccine regardless of if you’ve had COVID-19 or not. This is because experts don’t know how long people are protected from SARS-CoV-2 after recovering from coronavirus—so it’s still possible for reinfection to occur down the road. However, if you were treated for COVID-19 with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting the vaccine. If you are unsure about what treatments you had when sick with COVID-19, it’s best to consult with your doctor. 

Sources (listed in order of questions):

  1. Centers for Disease Control and Prevention (CDC) 
  2. Centers for Disease Control and Prevention (CDC) 
  3. www.covidvaccinefacts.org; Centers for Disease Control and Prevention (CDC)
  4. http://www.goodrx.com; Centers for Disease Control and Prevention (CDC)  
  5. U.S. Food & Drug Administration (FDA); Centers for Disease Control and Prevention (CDC); http://www.healthline.com 
  6. Centers for Disease Control and Prevention (CDC)
  7. Harvard Health Publishing (Harvard Medical School), Centers for Disease Control and Prevention (CDC)
  8. Centers for Disease Control and Prevention (CDC)
  9. Centers for Disease Control and Prevention (CDC); http://www.goodrx.com; healthline.com 
  10. Centers for Disease Control and Prevention (CDC)
  11. Centers for Disease Control and Prevention (CDC)