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, one of which has now received full FDA approval for people over 16. Vaccination programs have been rolled out nationwide. As of mid-August 2021, more than 73% of adults in the U.S. have received at least one dose of a COVID-19 vaccine.
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.
What Is COVID-19?
COVID-19 is the name of the disease that can occur as a result of the virus SARS-CoV-2 , a new type of coronavirus first detected in Wuhan, China in late 2019.
SARS-CoV-2 is transmitted through respiratory droplets, such as from a cough or sneeze, when people are in close contact of around six feet or less.
The virus can also spread by airborne transmission among people who are more than six feet apart. Airborne transmission occurs because aerosols containing the virus can be released when talking or breathing. This type of viral spread 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 you are experiencing these symptoms, please seek emergency medical attention.
People who have been infected but are asymptomatic and those who are presymptomatic (not yet showing symptoms) may still transmit the virus to others.
Since the start of the COVID-19 pandemic, multiple variants of the coronavirus have emerged. Many of these variants, including the Alpha (B.1.1.7) and Delta (B.1.617.2) variants, can be spread more easily than the original SARS-CoV-2 virus.
What COVID-19 Vaccines Are Available?
On August 23, 2021, the FDA granted full approval for the Pfizer-BioNTech COVID-19 Vaccine, known by the brand name Comirnaty, in people aged 16 and older. FDA approval was the result of extensive data demonstrating the safety and effectiveness of this vaccine.
In addition, the FDA has given emergency use authorization (EUA) to the Moderna COVID-19 Vaccine and the Johnson & Johnson (Janssen) COVID-19 Vaccine. The Pfizer-BioNTech vaccine continues to have emergency use authorization for people aged 12 to 15.
||Type of Vaccine
||Who Can Get This Vaccine?
||When Are You Fully Vaccinated?
||Date of Initial FDA Authorization
||12 years and older
||2 shots given 3 weeks apart (21 days)
||2 weeks after your second shot
||December 11, 2020
||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
||2 weeks after your shot
||February 27. 2021
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All three of these vaccines are administered through injection into the muscle of the upper arm.
They 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 get infected, develop severe symptoms, require hospitalization, or die from COVID-19. 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.
Most people need two doses of the Pfizer and Moderna vaccines to be fully vaccinated. For people with significantly weakened immune systems, such as organ transplant recipients, the Food and Drug Administration has authorized a third dose of these mRNA vaccines.
What COVID-19 Vaccines Are Under Development?
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.
What Is the Timeline for Vaccination?
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.
How Can I Get a COVID-19 Vaccine?
COVID-19 vaccines are 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.
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. If you have concerns about a specific vaccine, it is best to discuss them with your doctor.
Are COVID-19 Vaccines Safe?
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 363 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 Johnson & Johnson vaccines.
These side effects normally go away within a few days and pose no ongoing problems 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.
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 around 15 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.
The Johnson & Johnson vaccine has been associated with an increased risk of a condition called thrombosis with thrombocytopenia syndrome (TTS) in women under 50. The side effect is very rare, occurring approximately seven times per million vaccinations. After a brief pause in use of this vaccine, the FDA and CDC concluded that its benefits outweigh its risks, allowing vaccination to resume. No other authorized vaccines have been linked to TTS.
Although the COVID-19 vaccines are generally safe, there are some precautions to consider. Talk to your doctor before getting vaccinated if you:
- Have known allergies
- Currently have a fever
- Have symptoms of COVID-19 or were recently exposed to an infected person
- Are taking a blood thinner
- Have a bleeding disorder
- Are immunocompromised
- Take medicine that affects your immune system
- Are pregnant or trying to get pregnant
- Are breastfeeding
- Have inflammation of the heart muscle or the lining around the heart
- Have already received a different COVID-19 vaccine
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.
Who Shouldn’t Get the COVID-19 Vaccine?
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 12 years and older, and the Moderna and Johnson & Johnson vaccines in people 18 years and older.
How To Stay Safe After Vaccination
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.
People who have been vaccinated have strong protection against severe illness, hospitalization, and death from COVID-19. They also have some protection against infection. Nevertheless, vaccinated people can still contract COVID-19 and are able to spread the virus to others.
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:
- Avoiding large gatherings
- Keeping physical distance of at least six feet from other people
- Avoiding being in enclosed and/or poorly ventilated spaces with others
- Wearing a mask or other face covering when indoors or unable to maintain physical distance
- Washing your hands frequently
- Staying home and avoiding contact with others if you feel sick or have symptoms of COVID-19
Busting COVID-19 Vaccine Myths
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:
- COVID-19 vaccines do not give you the virus: The vaccines incorporate only small fragments of material taken from the coronavirus, and these fragments are unable to transmit the virus. In fact, by teaching your immune system to recognize the virus, the vaccines offer protection against COVID-19.
- COVID-19 vaccines do not affect your DNA: None of the vaccines have the potential to enter the nucleus of your cells where your DNA exists.
- COVID-19 vaccines do not affect female fertility: No studies have found there to be any effect of these or any other vaccines on a woman’s ability to get pregnant.
- COVID-19 vaccines are safe for women who are pregnant: Analysis of a growing body of data has shown that vaccination is safe during pregnancy. Vaccines also protect pregnant women who are at a higher risk of severe COVID-19. Some research indicates that vaccination during pregnancy and/or breastfeeding may even provide some protection to infants.
Sleep, Sickness, and Vaccines
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 because white blood cells (immune system cells) traveling to affected sites in the body can be 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 may mean less integrin and, as a result, 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 sleep apnea is associated with worse outcomes in people 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 Moderna vaccines].” Side effects can be offset by taking acetaminophen after vaccination.
Dr. Thorpy also reminds us that “the satisfaction of being vaccinated is often associated with better sleep at night.”
Ongoing COVID-19 Vaccine Research
Even though vaccines have already shown significant benefits, scientists are continuing investigation in other important areas of COVID-19 vaccine research, such as:
- The effectiveness of existing vaccines against mutated virus variants
- How long immune protection from vaccination lasts
- The possible development of booster shots to strengthen immunity
- The effectiveness of vaccines if the number or timing of doses is changed
- The safety and efficacy of some vaccines in children and adolescents
- How many people must be vaccinated to achieve broader population immunity
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.
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