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Johnson & Johnson/Janssen COVID-19 Vaccine: 8 FAQs Inc. Effectiveness, Safety, and Availability

Answers to the most common questions about the Johnson & Johnson COVID-19 Vaccine

The Johnson & Johnson vaccine was developed to prevent COVID-19, the infectious disease caused by the novel coronavirus SARS-CoV-2. It was authorized for emergency use by the FDA on February 27, 2021. It has been authorized for use on all patients aged 18 or older. Unlike other COVID-19 vaccines, the Johnson & Johnson vaccine is administered through only one dose. The vaccine has been shown to be both safe and effective in clinical trials.

The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

  1. How does the Johnson & Johnson COVID-19 vaccine work?
  2. Is the Johnson & Johnson COVID-19 vaccine safe?
  3. What are the side effects of the Johnson & Johnson COVID-19 vaccine?
  4. Who can get the Johnson & Johnson COVID-19 vaccine?
  5. What is the difference between the Johnson & Johnson, Pfizer, Moderna, and AstraZeneca vaccines?
  6. Are there any interactions with the Johnson & Johnson COVID-19 vaccine?
  7. Does the Johnson & Johnson COVID-19 vaccine stop the spread of COVID-19?
  8. How effective is the Johnson & Johnson COVID-19 vaccine?

1. How does the Johnson & Johnson COVID-19 vaccine work?

Like other COVID-19 vaccines, such as the Pfizer-BioNTech vaccine, the Johnson and Johnson vaccine focuses on the virus’s genetic instructions for building a spike protein. When a person receives these vaccines, their body produces the spike protein portion of the virus. This will not cause the disease, but it does allow the immune system to learn how to properly defend itself from the virus. Unlike other COVID-19 vaccine variants, the Johnson & Johnson vaccine does not deliver these instructions via RNA. Instead, it delivers them using double-stranded DNA, like the AstraZeneca vaccine.

To most people, the difference in how a vaccine delivers instructions may not mean much. In practical terms, this difference in construction allows for a much more easily storable vaccine. Unlike the Moderna and Pfizer variants, the Johnson & Johnson vaccine only needs to be refrigerated between 2-8 degrees Celsius. This makes it much more logistically practical.

2. Is the Johnson & Johnson COVID-19 vaccine safe?

The Johnson & Johnson COVID-19 vaccine has been shown in both manufacturer and clinical trials to be safe and effective. The vaccine has met all the safety standards set by the FDA. The vaccine is also subject to safety monitoring systems such as the CDC safety surveillance programs and Vaccine Adverse Event Reporting System (VAERS). These systems ensure that adverse events are monitored and recorded. In the event of unexpected severe side effects, experts will quickly evaluate and determine if there is a true safety concern.

Based on all currently available information, the Johnson & Johnson vaccine is considered to be very safe.

Research into a possible link between the vaccine and rare blood clots (called CVST) is ongoing and health bodies are regularly reassessing the situation. At the time of writing, it is widely agreed that the benefits of the vaccine drastically outweigh any risk. While we strive to keep the information in this article up to date, please check your local health authority for the latest information and regulations.

3. What are the side effects of the Johnson & Johnson COVID-19 vaccine?

Just like any other vaccine, the Johnson & Johnson COVID-19 vaccine produces a range of possible side effects. The list below includes some of the most common side effects but is not a complete list. Mild side effects typically subside after a few days, if they do not subside you should consult your doctor.

Common side effects:

In some rare cases, patients can experience allergic reactions. Seek emergency medical care if you experience any of the following symptoms after receiving the vaccine.

  • Skin rash
  • Wheezing
  • Tightness in the throat or chest
  • Difficulty talking or breathing
  • Swelling of the face, lips, tongue, or throat

4. Who can get the Johnson & Johnson COVID-19 vaccine?

The Johnson & Johnson COVID-19 vaccine has been approved for anyone above the age of eighteen. When it comes to the roll-out of the vaccine and when you will be eligible for vaccination, it will depend on your location and local regulations regarding vaccine distribution. At the time of writing this, in the US, people 16 and older are now eligible to receive the vaccine. In general, vaccines will be administered to higher-risk people first. In the case of COVID-19, this includes those with existing conditions and elderly people.

5. What is the difference between the Johnson & Johnson, Pfizer, Moderna, and AstraZeneca vaccines?

Each of the COVID-19 vaccines varies from one other. There is a range of effectiveness, vaccine content, and side effects. The Johnson & Johnson vaccine is the only one dose vaccine, others require follow-up doses. It is most similar to the AstraZeneca vaccine, while the Moderna and Pfizer vaccines are more closely related. This is because both the AstraZeneca and Johnson & Johnson vaccines transport their genetic instructions via DNA, rather than RNA. This makes them more durable and storable by refrigeration. In contrast, the Moderna and Pfizer-BioNTech vaccines must be stored at temperatures well below freezing. Furthermore, executives at Johnson & Johnson have announced that they will not charge more than $10 per dose, making this vaccine one of the cheapest available.

The best vaccine is whichever one is available to you. Whether it’s the Pfizer, Moderna, Johnson & Johnson, or AstraZeneca vaccine, they have all been shown to be safe and effective.

6. Are there any interactions with the Johnson & Johnson COVID-19 vaccine?

Currently, there are no known interactions with the Johnson & Johnson COVID-19 vaccine. However, it is not recommended that you receive any other vaccinations within 14 days of receiving the COVID-19 vaccine.

7. Does the Johnson & Johnson COVID-19 vaccine stop the spread of COVID-19?

Most vaccines produced to prevent viral diseases also help in reducing the spread of the disease. Unfortunately, it is not currently known if the COVID-19 vaccine will reduce transmission. Therefore, even if you have received the vaccine, you should take precautions to avoid spreading the disease as much as possible, such as wearing a mask and maintaining social distance, at least until more is known about the impact of vaccination on transmission.

8. How effective is the Johnson & Johnson COVID-19 vaccine?

A review of data from clinical trials presents the Johnson & Johnson vaccine lagging behind other vaccines in efficacy. While the Pfizer-BioNTech vaccine is 95% effective at preventing the virus, the Johnson & Johnson vaccine is only 66.3% effective. However, it is 100% effective at preventing hospitalization and death from the virus. For that reason, it can still be considered very effective.


The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

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