Janssen
The Janssen COVID-19 Vaccine is one of four vaccines for the COVID-19 virus available in the United States. In Feburary of 2021, it received FDA's Emergency Use Authorization (EUA) for use in people aged 18 years and older. But since May of 2022, it's no longer a first-choice vaccine because of the risk of a serious side effect of rare blood clots. It should only be used in certain cases, such as when the other COVID-19 vaccines can't be used or aren't available. If you're getting Janssen COVID-19 Vaccine as your primary vaccine, you'll only need one dose.
Note: As of May 2023, Janssen COVID-19 Vaccine is no longer available in the United States.
What is Janssen COVID-19 Vaccine?
What is Janssen COVID-19 Vaccine used for?
- Prevent COVID-19 infections in certain people aged 18 years and older
How Janssen COVID-19 Vaccine works
The Janssen COVID-19 Vaccine is a viral vector vaccine. It contains a slightly different, harmless version of the COVID-19 virus. When it's injected into your body, the vaccine tells your cells to make a part of the “spike protein” that's found on the virus that causes COVID-19. Your immune system recognizes that this spike protein doesn't belong in your body, so it produces antibodies against it. The antibodies tell other immune cells in your body to get rid of it. This teaches your body how to recognize the COVID-19 virus. So when you get infected with the real COVID-19 virus, your immune system is ready to fight and protect you from serious infection.
Drug facts
Side effects of Janssen COVID-19 Vaccine
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
Primary vaccination:
- Pain where the shot was given (33-59%)
- Headache (30-44%)
- Tiredness (30-44%)
- Muscle aches (24-39%)
- Nausea (12-16%)
- Fever (3-13%)
Booster dose:
- Pain where the shot was given (21-60%)
- Headache (27-42%)
- Tiredness (33-52%)
- Muscle aches (10-36%)
- Nausea (2-10%)
- Fever (6%)
Less Common Side Effects
- Redness or swelling where the shot was given
Janssen COVID-19 Vaccine serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Blood clots (thrombosis with thrombocytopenia syndrome): blurred vision, severe headaches, leg pain or swelling, chest pain, trouble breathing, stomach pain that won't go away, tiny blood spots on your skin in areas beyond where the shot was given
- Nervous system problems (Guillain-Barre syndrome): weakness or tingling in your arms or legs, trouble walking, trouble moving your mouth, jaw, or eyes, difficulty controlling your bladder or bowels
- Serious allergic reactions: trouble breathing, throat tightness, fainting, hives, rash, swelling of your face, lips, tongue, or throat
Pros and cons of Janssen COVID-19 Vaccine
Pros
- Works well to lower your risk of hospitalization and death if you're infected with COVID-19
- Primary series only require one dose
- Can be used as a booster shot for COVID-19
Cons
- Not authorized for people under 18 years of age
- Not a first-choice COVID-19 vaccine because of the risk for blood clots
- Lower rates of protection against the Omicron variant of COVID-19 compared with Comirnaty or Spikevax
Pharmacist tips for Janssen COVID-19 Vaccine
- The Janssen COVID-19 Vaccine will be injected into your muscle by a healthcare provider. This vaccine only requires one single injection.
- If you're receiving the Janssen COVID-19 Vaccine as a booster dose after completing initial vaccination with the Janssen COVID-19 Vaccine, the booster should be given at least 2 months after your dose of the Janssen COVID-19 Vaccine.
- If you're receiving the Janssen COVID-19 Vaccine as a booster dose after completing initial vaccination with one of the mRNA vaccines, such as Comirnaty (Pfizer-BioNTech) or Spikevax (Moderna), the booster should be given at least 5 months after completing the mRNA vaccination series.
- The Janssen COVID-19 Vaccine can cause discomfort, such as pain, redness, or swelling, where you received the shot. To help with these side effects, you can apply a cool washcloth over the area where you got the injection. Moving your arm around can also help.
- The Janssen COVID-19 Vaccine can also cause headaches, tiredness, fever, and muscle aches. If you develop a fever, be sure to drink plenty of fluids and dress in light clothing to avoid overheating.
- Usually, feeling uncomfortable because of pain or a fever is a normal sign that your immune system is building protection against the COVID-19 virus. But if any side effects get worse after 24 hours or don't go away after a few days, it's best to contact your healthcare provider.
- Don't take any over-the-counter medications, such as ibuprofen (Advil, Motrin), acetaminophen (Tylenol), or diphenhydramine (Benadryl), before receiving the Janssen COVID-19 Vaccine to prevent side effects. It's not known if they can affect how well the vaccine works. If needed, talk to your provider about taking these medications if you develop any side effects after getting the Janssen COVID-19 Vaccine.
- Some people have fainted after getting the Janssen COVID-19 Vaccine. To prevent injuries caused by fainting, be sure to sit down while receiving your injection and while your provider is monitoring you afterwards.
Common questions about Janssen COVID-19 Vaccine
How well Janssen COVID-19 Vaccine works to protect against COVID-19 changes as the coronavirus itself evolves. The initial clinical trials showed that Janssen COVID-19 Vaccine prevented 66% of laboratory-confirmed COVID-19 infections. But as different COVID-19 variants pops up, the effectiveness of Janssen COVID-19 Vaccine changed. Studies from the start of the recent Omicron surge has shown that a single dose of Janssen COVID-19 Vaccine was only prevented hospitalization from COVID-19 about 31% of the time. But if you get a booster, your chances of having to go to the hospital from serious COVID-19 goes down even more.
In May of 2022, the FDA limited who can use Janssen COVID-19 Vaccine after confirming that this vaccine can put people at risk for a rare, but serious blood clotting condition called thrombocytopenia syndrome (TTS). Right now, this vaccine can only be used by people aged 18 years and older under certain conditions, such as when the other COVID-19 vaccines can't be used or aren't available. Talk with your provider if you've any questions about which COVID-19 vaccine is the best choice for you.
It's possible for you to get Janssen COVID-19 Vaccine as a booster if you've received a different brand of vaccine as your primary series. But if you can, the CDC recommends that you use Comirnaty (Pfizer-BioNTech COVID-19 vaccine) or Spikevax (Moderna COVID-19 vaccine) as your booster instead. This is due to the fact that the Janssen COVID-19 Vaccine can cause serious side effects, such as blood clots. But, the Janssen COVID-19 Vaccine can be considered in certain situations. If you plan to receive the Janssen COVID-19 Vaccine as a booster shot and you completed primary vaccination with Comirnaty or Spikevax, you should wait at least 5 months after you completed your vaccination series to get the Janssen COVID-19 Vaccine.
The CDC and American College of Obstetricians and Gynecologists recommend that all pregnant females get vaccinated, including with a booster shot, against COVID-19. If you're pregnant, you're more likely to get very sick from COVID-19 compared to those who aren't pregnant. Also, COVID-19 raises your risk of preterm birth and stillbirth. Early data from studies that used the same version of the virus as the Janssen COVID-19 Vaccine showed no harmful effects on unborn babies. There's an ongoing pregnancy registry that monitors the health of mothers and babies born to mothers who got the Janssen COVID-19 Vaccine during pregnancy. If you've received this vaccine while pregnant, you're encouraged to enroll in the registry.
The CDC and American College of Obstetricians and Gynecologists recommend that people who are breastfeeding get vaccinated against COVID-19. While more research is needed to better understand the effects of Janssen COVID-19 Vaccine on your milk supply and baby, there's growing evidence that shows COVID-19 vaccines are safe while breastfeeding. If you're breastfeeding, you don't need to avoid or stop nursing your baby if you receive the Janssen COVID-19 Vaccine.
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Risks and warnings for Janssen COVID-19 Vaccine
Janssen COVID-19 Vaccine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Serious blood clots (thrombosis with thrombocytopenia syndrome)
- Risk factors: Females 18 to 49 years old
Although rare, the Janssen COVID-19 Vaccine can cause a serious blood clotting condition called thrombosis with thrombocytopenia syndrome. This is a condition that can cause blood clots in the brain, lungs, stomach, and legs, along with low levels of platelets (a type of blood cell that helps you stop bleeding). This condition is most common in females 18 to 49 years old. In some cases, it led to death. If you develop any signs of a blood clot, such as chest pain, shortness of breath, swelling or pain in your legs, stomach pain that won't go away, severe headaches, blurred vision, or tiny blood spots on your skin in areas beyond where the shot was given, get emergency medical help right away.
Nervous system problems (Guillain-Barre syndrome)
- Risk factors: Age 50 years and older
Rarely, the Janssen COVID-19 Vaccine can cause Guillain-Barre syndrome, which is a condition where your immune system damages your nerves. This can lead to muscle weakness and paralysis. The risk of this condition is highest in the first 42 days after receiving the Janssen COVID-19 Vaccine. If you experience weakness or tingling in your arms or legs, trouble walking, trouble moving your mouth, jaw, or eyes, or difficulty controlling your bladder or bowels, get medical help right away.
Lower response in people with weakened immune systems
- Risk factors: Conditions that weaken your immune system (e.g., HIV/AIDS) | Taking medications that lower your immune system (e.g., prednisone, tacrolimus (Prograf))
If you have a weakened immune system, either due to a medical condition or medication that you're taking, your immune system might not respond as well to the Janssen COVID-19 Vaccine. This means you might not build up as strong of protection against the COVID-19 virus. Let your provider know if you have a weakened immune system.
Janssen COVID-19 Vaccine dosage
Typical dosage for Janssen COVID-19 Vaccine
- Primary vaccination: The typical dose is a one-time injection of 0.5 mL into the muscle.
- Booster: If you've received Janssen COVID-19 Vaccine, you can choose this vaccine as a booster if it's been at least 2 months since your primary dose. The typical dose is a one-time injection of 0.5 mL into the muscle.
