This article is for informational purposes only. Consult your local medical authority for advice. For up-to-date information on the COVID-19 outbreak and vaccine, visit cdc.gov.
Since the World Health Organization (WHO) declared COVID-19 to be a pandemic in March 2020, intensive efforts have focused on developing a vaccine that could minimize the disease’s impact.
In the United States, the Food and Drug Administration (FDA) has given emergency use authorization to three different vaccines, and vaccination programs have been rolled out nationwide.
Because COVID-19 is a vital public health issue, it’s important for people to have access to dependable, science-based information about COVID-19 vaccines.
SARS-CoV-2 is most easily transmitted through respiratory droplets when people are in close contact of around six feet or less. The virus also spreads through airborne transmission, by aerosols that are released when talking or breathing, and remain suspended in the air for an extended amount of time.
Airborne virus transmission can occur even when people are more than six feet apart and is more likely in enclosed spaces with poor ventilation. Less often, the coronavirus can be transmitted by touching contaminated surfaces.
Symptoms of COVID-19 can vary significantly among people infected with the virus. While some people are asymptomatic, others develop major symptoms, such as fever, cough, difficulty breathing, loss of taste and/or smell, headache and/or body ache, nausea, vomiting, diarrhea, nasal congestion, and/or runny nose.
In severe cases, COVID-19 can cause trouble breathing, pain or pressure in the chest, confusion, inability to wake up or stay awake, and pale/discolored skin, lips, or nail beds. If experiencing these symptoms, please seek emergency medical attention.
The FDA has given three COVID-19 vaccines authorization for emergency use, the Pfizer-BioNTech COVID-19 Vaccine, the Moderna COVID-19 Vaccine, and the Janssen (Johnson & Johnson) COVID-19 Vaccine. Each of these vaccines is administered through injection into the muscle of the upper arm.
|Vaccine Name||Type of Vaccine||Who Can Get This Vaccine?||Required Doses||When Are You Fully Vaccinated?||Date of Initial FDA Approval|
|Pfizer-BioNTech||mRNA||12 years and older||2 shots given 3 weeks apart (21 days)||2 weeks after your second shot||December 11, 2020|
|Moderna||mRNA||18 years and older||2 shots given 4 weeks apart (28 days)||2 weeks after your second shot||December 18, 2020|
|Janssen (Johnson & Johnson)||Viral vector vaccine||18 years and older||1 shot||2 weeks after your shot||February 27. 2021|
All three vaccines have been tested in clinical trials involving tens of thousands of adults and adolescents. In those studies, people taking the vaccines were significantly less likely to have COVID-19, develop severe symptoms, or require hospitalization. Compared with placebo, the vaccines offered considerable protection with minimal side effects.
The vaccines developed by Pfizer and Moderna are mRNA vaccines. This type of vaccine utilizes a harmless, synthetic fragment of genetic material from the virus to train the immune system to recognize and attack the virus itself.
The vaccine developed by Janssen, a component of the company Johnson & Johnson, is a viral vector vaccine. It incorporates a genetic fragment of SARS-CoV-2 into a deactivated common cold virus. This enables the immune system to better identify and attack the coronavirus.
While three vaccines are currently available in the United States, additional vaccines are under development. They may become authorized if data from research studies supports their safety and effectiveness.
A viral vector vaccine developed by AstraZeneca is in use in Europe but has not been authorized by the FDA. A different type of vaccine, called a protein subunit vaccine, developed by Novavax is still being evaluated in clinical trials. A protein subunit vaccine works by incorporating a small protein from the coronavirus that empowers the immune system to recognize and attack the virus.
Mutations that lead to new strains of SARS-CoV-2 may lead to modified or booster vaccines designed to attack a broader scope of coronavirus variants.
Vaccination has been ongoing since the first COVID-19 vaccine was authorized by the FDA in December 2020. Vaccine distribution involves federal management, but actual vaccination programs are administered primarily by state and local authorities.
All states have now made the vaccines available to all approved age groups, most recently in the 12-15 year age group for the Pfizer vaccine. Pfizer has also announced that it has started clinical trials in children 6 months to 11 years of age. Moderna continues to study its vaccine in a younger population.
The COVID-19 vaccine is currently available nationwide to all clinically approved age groups (see table for details).
To learn about where to get vaccinated in your area, contact your state and local health department for information. You can also ask your doctor for guidance.
A Vaccine Finder website has been established in cooperation with the CDC to provide information about vaccine availability in different states. Vaccines may be offered in various settings, including health clinics, medical offices, hospitals, pharmacies, and mass vaccination sites.
In many areas, programs have been created for you to register your interest in receiving the vaccine. By joining these registries, you can receive updates about vaccination sites and scheduling appointments for vaccination.
It is important to note that you generally cannot choose which brand of vaccine that you will receive. However, many sites have been reporting the vaccine type/manufacturer they are administering.
Studies in tens of thousands of people in multiple countries have shown that COVID-19 vaccines are safe, and this safety record has been reinforced since December 2020 with over 75 million doses having been administered in the United States.
Some of the most common side effects are pain or swelling in the arm where you receive the shot, fever, chills, and headache. Many people also experience significant tiredness or fatigue, a side effect found in the Pfizer, Moderna, and Janssen vaccines.
These side effects normally go away within a few days and pose no ongoing problem after vaccination. For the Pfizer and Moderna vaccines that require two doses, side effects can occur with either dose but have been more frequently reported after the second vaccine.
For all three vaccines, there have been extremely rare reports of severe allergic reactions. You will normally be asked to stay at the vaccination site for 15 to 30 minutes after receiving the shot to monitor for any adverse response. During this time, any signs of allergic reaction, such as facial swelling, rash, difficulty breathing, or dizziness should be reported to medical officials immediately.
Although the COVID-19 vaccines are generally safe, there are some precautions to consider. Talk to your doctor before getting vaccinated if you:
These factors do not disqualify a person from getting vaccinated, but reviewing them with a doctor can help ensure safe vaccine administration.
When you arrive at an appointment for vaccination, you can expect to receive a document that explains the potential side effects. As you review this form, you can bring up any questions or concerns with medical staff at the vaccine site.
People who have had previous allergic reactions to a prior dose of the COVID-19 vaccine or to ingredients contained in these vaccines should not be vaccinated.
Vaccines are not currently authorized for use in children. The Pfizer vaccine is authorized in people aged 16 years and older, and the Moderna and Janssen vaccines in people 18 years and older.
Vaccines do not offer immediate protection against the coronavirus. It takes time for your body’s immune system to develop a response, and during that time, you can still be susceptible to COVID-19. In addition, while the vaccines have been shown to prevent serious illness, it is not yet known if they stop transmission of the virus.
For these reasons, it is important to maintain basic precautions against COVID-19 after vaccination. These measures can enhance protection for you and others and include:
Even though large research studies have shown the safety of COVID-19 vaccines, some myths about them continue to be spread online. Knowing the facts can help bust those myths:
Getting a sufficient amount of quality sleep is important for your immune system. Research about sleep and the COVID-19 vaccines is not yet available, but studies of other types of vaccines have found that sleep deprivation can reduce their effectiveness.
Sleep affects a number of different immune factors, and adequate sleep is associated with a reduced risk of infection, improved infection outcome, and better vaccine response. On the other hand, sleep deprivation has been shown to impair how the body protects itself. White blood cells (immune system cells) traveling to affected sites in the body are diminished.
Another way sleep loss is associated with decreased immune response is through our T cells (active participants in immune response): lack of sleep increases levels of stress hormones, which reduce levels of integrin (a molecule that helps T cells stick to virus-infected cells). Less sleep = less integrin = less-effective T cells.
Sleep deficiency also affects immune response to vaccines, including the flu shot: patients who are sleep deprived (<7 hours of sleep per night) have a lower immune system response and are 11 times more likely to remain unprotected despite vaccination.
Those with sleep disorders may wonder how the vaccine may impact their ongoing treatments, or whether it could exacerbate their symptoms. According to Dr. Michael Thorpy, Professor of Neurology at Albert Einstein College of Medicine and Director of Sleep-Wake Disorders Center at Montefiore Medical Center, “There is no evidence that it is likely to worsen any sleep disorder, and all patients are encouraged to be vaccinated as soon as possible.” Vaccinating patients with sleep apnea is especially important, according to Thorpy, as it is associated with worse outcomes for those who get COVID-19.
With regard to the vaccine, Thorpy adds that “adverse effects are rare but mild, such as headache, and often associated with the second dose [of Pfizer or Janssen vaccines].” Side effects can be offset by taking acetaminophen before vaccination or even after.
Dr. Thorpy also reminds us that “the satisfaction of being vaccinated is often associated with better sleep at night.”
Even though vaccines have already shown significant benefits, scientists are continuing investigation in other important areas of COVID-19 vaccine research, such as:
In addition, the FDA and CDC are continuing multiple programs that monitor vaccine responses to quickly detect reports about adverse effects and work with healthcare providers to ensure safe vaccination programs. If you have any questions about the vaccine, your eligibility, or any adverse reactions, please contact your healthcare provider for further guidance.