COVID-19 Booster Shots: Everything You Need to Know

January 10, 2022
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feature image BOOSTER SHOTS

In the United States, three vaccine-makers (Pfizer, Moderna, and Johnson & Johnson) have been given the green light from the U.S. Food and Drug Administration (FDA) to administer COVID-19 booster shots. Of the three brands, Pfizer was the first to take action, administering booster shots since September 24. 

As states continue to report a surge in COVID-19 cases caused by the Omicron variant, medical professionals, government leaders, and local communities are urging citizens to get a booster shot as soon as possible.

There’s been much speculation surrounding booster shots: Are they effective against the Omicron variant? Who’s eligible to get a booster shot? Should the booster be the same brand as your initial vaccine? 

Read on to know more about the basics of booster shots and some of the common misconceptions connected with them. 

What is a COVID-19 Booster Shots?

A COVID booster shot is simply an additional dose from a vaccine given to someone a few months after they’ve been fully vaccinated to help maintain their level of immunity. 

Why do you need to get a booster shot?

COVID-19 Booster Shots

As with other booster shots from other brands or for different diseases, none of them are 100% effective. For the most part, what they will do is stimulate your body’s B & T cells. This will help prevent you from having a severe infection as natural immunity from past vaccines will eventually wane over time.  

Now that many people have been required to report back to the office, and with preliminary reports of vaccines being ineffective against blocking Omicron, the need for a booster shot is vital to keep your immune system in tip-top shape. 

Here were some of the results:

  • A study done by CDC reports that the efficacy of an mRNA vaccine dropped from 74.7% to 53.1% in nursing homes during the period March to July 2021.
  • In adults living in New York, it was reported that vaccine efficacy dropped from 91.7% to 79.8% from May to July 2021 (these were the months where the Delta variant was at its peak).
  • A study done in Qatar stated that protection from infection of COVID-19 grows rapidly after the first dose, peaks one month after getting the 2nd dose, and gradually declines after four months. The same study also found that those vaccinated were more than 90% protected from the worst possible outcomes when infected with COVID-19.

Does this mean the vaccines are ineffective?

Not at all! As mentioned earlier, the efficacy of a vaccine will wane over time. Multiple reports have shown that the vaccine can indeed prevent a severe infection, even in the older population and those with comorbidities.

As Melissa Higdon, a faculty member of the Johns Hopkins Bloomberg School of Public Health said: “The main objective of the Covid vaccine is to prevent severe disease and death, and they are still doing a good job at that.” 

Who can get a booster shot?

Those authorized or approved for a booster shot will vary depending on the brand of your initial vaccine. Here’s what the CDC recommends

If your initial vaccination was from


Anyone who is 12 years old or older that’s been fully vaccinated for more than five months is eligible for a booster shot from any of the brands available. 


Adults 18 years old and older who’ve been fully vaccinated for more than six months are eligible for a booster shot from any of the brands available. 

Johnson & Johnson

Adults aged 18 years old and above who’ve been fully vaccinated for more than two months are eligible for a booster shot from any of the brands available.

What are the potential side effects after getting a booster shot?

Regardless of the type of brand you choose for your booster (but CDC recommends choosing Pfizer or Moderna over Johnson & Johnson), you can expect to experience mild to moderate symptoms that typically resolve in a couple of days:

  • Fever
  • Pain on the injection site
  • Fatigue
  • Muscle pain
  • Headache
  • Chills
  • Nausea

There have also been rare cases of other side-effects attributed to booster shots not mentioned above. Here are some rare side-effects depending on the brand of your booster:


  • Anaphylaxis: a severe allergic reaction that occurs within seconds to minutes after being exposed to something you’re allergic to. It’s also important to note that this allergic reaction is common with other vaccinations and can be treated quickly.
  • Myocarditis: an inflammation of the heart muscle. This rare side-effect has been mostly reported in males under 30 following their second dose of a COVID-19 vaccine and can be treated through rest and medication.


Both of the aforementioned rare side effects for Pfizer (Anaphylaxis & Myocarditis) can also be expected from the Moderna booster. 

Another rare side effect of a Moderna booster shot is swollen lymph nodes in the underarm. 

Johnson & Johnson

  • Thrombosis with thrombocytopenia syndrome: a rare condition in which a person has blood clots and a low blood platelet count. This syndrome has been more common in women between the ages of 30-40. 
  • Guillain-Barré Syndrome (under monitoring by the CDC & FDA): a rare disorder where the body’s immune system leads to muscle weakness and sometimes paralysis. This syndrome has been mostly reported in males 50 years old and above. 

Where can you get a booster shot or vaccination?

If you’re already fully vaccinated, you can contact the location and set an appointment where you initially got your vaccine. 

If you’re looking to get a booster shot or vaccination from a different location, here’s what you can do

  1. Visit
  2. Check your local pharmacy’s website if they’re participating in the Federal Retail Pharmacy Program. If so, check to see if appointments are available. 
  3. Contact your state health department.
  4. Check your local news outlets. 

Can you get another vaccination at the same time as your COVID-19 booster or vaccine?

Yes, according to the CDC. COVID-19 boosters and vaccines may be administered without any regard to other vaccines. Just make sure to have each injection administered on different sites (separated by at least one inch or more).
Aside from receiving a vaccination or booster shot, the other best solution to curb the spread of rising infections is to get tested whenever you or someone you know starts to develop any COVID-related symptoms.

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