COVID-19Common question

How do inactivated vaccines work?

Inactivated vaccines use the killed version of the germ that causes a disease.

Inactivated vaccines usually don't provide immunity (protection) that's as strong as live vaccines. So you may need several doses over time (booster shots) in order to get ongoing immunity against diseases.

What does a booster shot do?

Typically, you would get a booster after the immunity from the initial dose(s) naturally starts to wane. The booster is designed to help people maintain their level of immunity for longer.

Can you still get COVID-19 after booster vaccine?

COVID-19 is still a risk. Getting a booster shot doesn't guarantee you won't be infected with the coronavirus. But it can help your immune system build protection against severe disease or hospitalization -- including from the delta variant.

Is Covid vaccine booster safe?

Even for them, however, the risk is very low and vastly outweighed by the risks of Covid-19 infection. The FDA recognized this safety profile when it authorized booster shots for those in “at risk” groups. The evidence for effectiveness is still emerging, but what is known today is ample.

How is the Novavax vaccine different from other COVID-19 vaccines?

While other vaccines trick the body's cells into creating parts of the virus that can trigger the immune system, the Novavax vaccine takes a different approach. It contains the spike protein of the coronavirus itself, but formulated as a nanoparticle, which cannot cause disease.

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How does the Novavax COVID-19 vaccine work?

The Novavax vaccine uses a telltale piece of the coronavirus: the notorious spike protein. All alone, the spike protein is harmless and can't cause COVID-19. When your immune system encounters the lonely spike protein, it produces antibodies against it. This gives you protection against future COVID-19 infection.

How does the Johnson & Johnson COVID-19 vaccine differ from mRNA?

The ultimate difference is the way the instructions are delivered. The Moderna and Pfizer vaccines use mRNA technology, and the Johnson & Johnson vaccine uses the more traditional virus-based technology. mRNA is essentially a little piece of code that the vaccine delivers to your cells.

Should everyone get a COVID-19 booster shot?

Booster vaccines are available right now, but at this time, the CDC is not recommending them for everyone. Eligible individuals may “mix and match” the vaccines, meaning they may choose any of the three COVID-19 vaccines authorized in the U.S. to receive as a booster dose.

Is the Pfizer COVID-19 booster vaccine safe?

The additional dose was safe and tolerable, and consistent with what was known about the vaccine, the companies said. The study was carried out while the highly contagious Delta variant was prevalent, the companies said, suggesting the booster helps protect against the contagious strain.

What are some of the serious side effects of the COVID-19 vaccine?

Rare serious adverse events have been reported after COVID-19 vaccination, including Guillain-Barré syndrome (GBS) and thrombosis with thrombocytopenia syndrome (TTS) after Janssen COVID-19 vaccination and myocarditis after mRNA (Pfizer-BioNTech and Moderna) COVID-19 vaccination.

How long after Pfizer COVID-19 vaccine booster is it effective?

The authors explain: “In this study, we estimated effectiveness starting from day 7 after the third dose, which is similar to the period used to define full vaccination after the second dose. Our choice is supported by high concentrations of antibodies in individuals 7 days after administration of the third dose.”

Do COVID-19 vaccine boosters work?

Results from Israel indicate that a booster dose greatly lowers the risk of severe illness. Boosters also prevent infection. This reduces the spread of SARS-CoV-2 among vaccinated and unvaccinated individuals. It isn't yet clear how long protection from boosters will last, but the world can't wait to find out.

How long will it take to build immunity after getting the COVID-19 vaccine?

It takes time for your body to build protection after any vaccination. People are considered fully vaccinated two weeks after their second shot of the Pfizer-BioNtech or Moderna COVID-19 vaccine, or two weeks after the single-dose J&J/Janssen COVID-19 vaccine.

What are some of the common side effects of Pfizer COVID-19 vaccine booster shots?

Fatigue and pain at the injection site were the most commonly reported side effects, and overall, most side effects were mild to moderate. However, as with the 2-shot primary series, serious side effects are rare, but may occur.

Is it normal to have side effects after second COVID-19 vaccine?

Side effects after your second shot may be more intense than the ones you experienced after your first shot. These side effects are normal signs that your body is building protection and should go away within a few days.

How does the COVID-19 vaccine boost your immune system?

Vaccines work by stimulating your immune system to produce antibodies, exactly like it would if you were exposed to the disease. After getting vaccinated, you develop immunity to that disease, without having to get the disease first.

Are there any long term effects of COVID-19 vaccine?

Serious side effects that could cause a long-term health problem are extremely unlikely following any vaccination, including COVID-19 vaccination. Vaccine monitoring has historically shown that side effects generally happen within six weeks of receiving a vaccine dose.

How long is the stability of the Pfizer-BioNTech COVID-19 vaccine?

Pfizer-BioNTech has submitted data to FDA supporting the stability of their COVID-19 vaccine when stored for up to one month (31 days) at 2°-8°C (standard refrigerator temperature).

Is the COVID-19 vaccine safe if you have heart problems?

Not only are the vaccines safe for people with a history of heart disease, they are essential. People with heart disease are at increased risk of severe complications from COVID-19.

How many doses of COVID-19 vaccine will I need to get?

The number of doses needed depends on which vaccine you receive. To get the most protection:

• Two Pfizer-BioNTech vaccine doses should be given 3 weeks (21 days) apart.
• Two Moderna vaccine doses should be given 1 month (28 days) apart.
• Johnson & Johnsons Jansen (J&J/Janssen) COVID-19 vaccine requires only one dose.

If you receive a vaccine that requires two doses, you should get your second shot as close to the recommended interval as possible. However, your second dose may be given up to 6 weeks (42 days) after the first dose, if necessary.. You should not get the second dose earlier than the recommended interval.

Who should not get the Moderna COVID-19 vaccine?

If you have had a severe allergic reaction (anaphylaxis) or an immediate allergic reaction, even if it was not severe, to any ingredient in an mRNA COVID-19 vaccine (such as polyethylene glycol), you should not get an mRNA COVID-19 vaccine.

How many shots do I need with the Pfizer or Moderna COVID-19 vaccine?

If you receive a Pfizer-BioNTech or Moderna COVID-19 vaccine, you will need 2 shots to get the most protection.

What vector is used in the AstraZeneca and Johnson & Johnson COVID-19 vaccines?

The virus vector being used in the Johnson & Johnson and AstraZeneca vaccines is an adenovirus, a common type of virus that typically causes mild cold symptoms when it infects someone.

COVID-19 viral vector vaccines inject a harmless adenovirus vector

How effective is the J&J Janssen COVID-19 vaccine?

The J&J/Janssen COVID-19 Vaccine was 66.3% effective in clinical trials (efficacy) at preventing laboratory-confirmed COVID-19 infection in people who received the vaccine and had no evidence of being previously infected. People had the most protection 2 weeks after getting vaccinated.

Is it safe to take the J&J/Janssen COVID-19 vaccine?

After receiving the J&J/Janssen COVID-19 Vaccine, there is risk for a rare but serious adverse event—blood clots with low platelets (thrombosis with thrombocytopenia syndrome, or TTS). Women younger than 50 years old should especially be aware of their increased risk for this rare adverse event.