What are your concerns?

Hard to understand

Or copy link


Ask Doctor for Free

Be the first to let Hello Doctor know your thoughts!

US CDC Prefers Pfizer, Moderna Vaccines Over J&J — Find Out Why

    US CDC Prefers Pfizer, Moderna Vaccines Over J&J — Find Out Why

    All vaccines are safe and effective against the severe cases of COVID-19. However, even experts have their preferred vaccine brand. The US Center for Disease Control (CDC), for instance, recommends Pfizer and Moderna over the single-shot J&J vaccine. These three are among the vaccines used here in the Philippines. What’s the reason behind this preference? Find out here.

    Why the CDC Prefers Pfizer, Moderna Over J&J1

    The CDC recommendation states that they prefer Pfizer and Moderna over the J&J vaccine for the prevention of COVID-19 in people 18 years and up.

    Officials said they made the recommendation after learning that a rare blood clotting disorder is more common in people who received the single-dose vaccine than they previously believed.

    In a mid-December report, the United States recorded 54 cases of thrombosis with thrombocytopenia since the vaccine’s approval. Nine of those who developed the condition died: seven women, two men.

    Although this was the primary factor, the experts also weighed in the vaccine effectiveness. They noted that the J&J vaccines’ effectiveness is lower compared to the mRNA giants, Pfizer and Moderna.

    They also stated that while Pfizer and Moderna list myocarditis (inflammation of the heart muscle) as a rare side effect, the risk is still lower compared to the blood clot risk after receiving the J&J vaccine.

    What Is Thrombosis with Thrombocytopenia Syndrome (TTS)?

    The side effect in question, thrombosis with thrombocytopenia syndrome, is a rare blood clotting disorder.

    Blood clot formation is a prerequisite to the wound healing process. If you cut your finger, the tiny clumps of blood that form at the surface help stop the bleeding. However, blood clots that form within the blood vessel and block circulation (thrombosis) could be dangerous.

    Thrombocytopenia, on the other hand, means low platelet count. Like thrombosis, it is also dangerous because platelets stop bleeding by promoting blood clotting.

    It is rare for a person with a blood clotting disorder to have a low platelet count. Usually, when you have a low platelet count, you’ll have difficulty forming blood clots.

    The fact that the J&J vaccine is associated with more cases of TTS than what the experts initially believed solidified their decision to prefer Pfizer and Moderna.

    Note that besides J&J, AstraZeneca has also been linked to TTS. The United States currently does not approve the use of AstraZeneca.

    Why US Authorities Continue To Support the J&J Vaccine

    After learning more about TTS, the rare blood clot disorder associated with the J&J vaccine, you may be wondering, “Why do health authorities continue to support it?” There are several reasons.

    First, experts believe that receiving any vaccine is far better than being unvaccinated. COVID-19, after all, doesn’t just cause hospitalization and intubation; it might also lead to long-term side effects.

    Secondly, TTS “continues to be a rare event.”

    And finally, in the United States, J&J is the only available vaccine for people who can’t — or won’t — get an mRNA vaccine. Some people might also prefer J&J because they don’t like getting two doses.

    They also mentioned that withdrawing support for the previously approved vaccine means people have fewer choices, and that may have an effect on the people’s confidence in the COVID-19 vaccination program.

    Key Takeaways

    The US Center for Disease Control made a statement saying they prefer mRNA vaccines, Moderna and Pfizer, over the viral vector J&J vaccine. The recommendation was made after the officials learned that the cases of thrombosis with thrombocytopenia syndrome (TTS) after J&J vaccination were higher than they initially thought. They also considered the vaccine effectiveness. Despite this, they continue to support the single-shot vaccine after weighing the benefits and risks.

    More Health News here.


    BMI Calculator

    Use this calculator to check your body mass index (BMI) and find out if you're at a healthy weight. You can also use this tool to check your child's BMI.



    Hello Health Group does not provide medical advice, diagnosis or treatment.


    1 CDC recommends Pfizer, Moderna vaccines over J&J’s, https://edition.cnn.com/2021/12/16/health/johnson-vaccine-acip-recommendation-mrna-preferred/index.html, January 28, 2022

    2 Safety of COVID-19 Vaccines, https://doh.gov.ph/Vaccines/Safety-of-COVID-19-Vaccines, January 28, 2022

    3 The Link Between J&J’s COVID Vaccine and Blood Clots: What You Need to Know, https://www.yalemedicine.org/news/coronavirus-vaccine-blood-clots#:~:text=The%20clotting%20disorder%20is%20called,over%2015%25%20of%20cases)., January 28, 2022

    4 Myocarditis and Pericarditis After mRNA COVID-19 Vaccination, https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myocarditis.html, January 28, 2022

    5 Different COVID-19 Vaccines, https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines.html, January 28, 2022

    Picture of the authorbadge
    Written by Lorraine Bunag, R.N. Updated Feb 02
    Fact Checked by Vincent Sales
    Next article: