Johnson & Johnson COVID vaccine boosters: What to know if you got J&J

The US Centers for Disease Control and Prevention recommended booster shots for all recipients of Johnson & Johnson’s coronavirus vaccine last week, saying everyone who got the one-dose shot can get another dose of Johnson & Johnson at least two months after they were vaccinated– or a booster shot of Pfizer or Moderna. 

The official recommendation followed a lengthy discussion by the CDC’s independent advisory committee, with members discussing guidance on who should receive boosters of Moderna’s and Johnson & Johnson’s COVID-19 vaccines, which received the US Food and Drug Administration’s authorization this week. The FDA also authorized a heterologous booster dose for all adults who qualify for one, meaning people can now “mix and match” vaccines for a booster. 

Read more: CDC says people can ‘mix and match’ boosters: What to know

Fewer people have gotten Johnson & Johnson’s one-dose vaccine than Pfizer or Moderna. About 15 million people have been vaccinated with J&J, according to the CDC, a relatively small number compared with those vaccinated with Pfizer or Moderna. This is partly because it was available in the US later than both mRNA vaccines, production issues resulted in millions of wasted doses, and use was paused briefly in April after concerns over a link to a rare but serious blood clotting disorder (mostly in women under age 50) that isn’t seen with the mRNA vaccines. 

People who received Moderna or Pfizer’s COVID-19 vaccines are eligible for a booster if they’re an adult at risk of severe COVID-19, either because of their age, underlying medical condition or where they live or work. The fact that boosters are recommended for all people who got Johnson & Johnson is based on research showing it’s less effective than Pfizer and Moderna, with some experts arguing Johnson & Johnson should’ve been a two-dose series from the beginning. 

Those who got the one-dose J&J vaccine, including immunocompromised people, were initially left out of the country’s booster shot plans because of a lack of data on the one-dose vaccine. The booster rollout in general is a controversial one — members of the World Health Organization have called on countries such as the US to slow the process of giving booster doses to people who are already vaccinated because much of the world remains unvaccinated against COVID-19. As few as 3.1% of people in low-income countries have had a coronavirus vaccine, according to Our World in Data.

Even as the CDC recommends boosters for a large swath of vaccinated adults in the US, all three COVID-19 vaccines remain protective against severe disease and death. Before the CDC’s official recommendation, some committee members argued we’re losing sight of what a vaccine is designed to do, which is not to prevent all infections, but to protect against severe disease. 

As the booster campaign rolls on, here’s what to know if you qualify for a booster because you got the J&J. 

Does it have to be another shot of J&J?

No. You can get any of the three COVID-19 vaccines available, meaning your choice can depend on your personal circumstances or preference. Both Johnson & Johnson’s and Pfizer’s boosters are the same dosage as the original series, while Moderna’s booster is a smaller dose than its original series. 

However, some committee members expressed concerns over recommending a second dose of Johnson & Johnson to women under age 50, who are at a higher risk for the very rare but also very serious blood clotting disorder associated with the vaccine (these clots require different treatment than the clots that occur from things such as taking birth control pills or riding on an airplane). 

Importantly, this risk isn’t associated with the Pfizer or Moderna vaccines. There is also the rare risk of a neurological disorder linked to Johnson & Johnson, occurring mostly in older men. In clinical guidance issued this week, meant to help walk eligible adults through choosing a booster dose, the CDC said that patients with a history of Guillain-Barré syndrome should “discuss the availability of mRNA COVID-19 vaccines” for protection against the coronavirus. The CDC also issued guidance that women under age 50 “should be made aware of the rare risk of TTS after receipt of the Janssen COVID-19 vaccine and the availability of other currently FDA-approved or FDA-authorized COVID-19 vaccines.”

CDC committee member Dr. Pablo Sanchez, said that while he agrees people who received Johnson & Johnson should get a second dose, “I would prefer that those individuals get an mRNA vaccine,” he said. 

Although data on “mixing vaccines” in the US is limited, it’s been done for months in other countries, where some individuals have received a dose of AstraZeneca (a viral vector vaccine like Johnson & Johnson) combined with a dose of mRNA vaccine. Preliminary data on mixing COVID-19 vaccines for boosters in the US found that while all three COVID-19 vaccines used as boosters for J&J recipients elicited strong responses, Moderna’s and Pfizer’s boosters elicited much stronger antibody responses — 76-fold and 35-fold, respectively — than a second dose of Johnson & Johnson (four-fold). While impressive, antibody response is not the full picture of immunity. 

What if I’m immunocompromised and got J&J? 

Immunocompromised people who received Johnson & Johnson and are “moderately or severely immunocompromised” should get a booster of any COVID-19 vaccine at least two months after the single dose. This is the same recommendation for everyone else who got Johnson & Johnson, but given that people with a suppressed immune system usually aren’t able to mount as strong an immune response, it may be especially important they seek out a second dose of COVID-19 vaccine. 

Although very few immunocompromised people likely received Johnson & Johnson compared to Moderna or Pfizer, a CDC committee member said, those who did were neglected in the CDC’s initial recommendation for an extra dose for moderately or severely immunocompromised folks for lack of data. (Immunocompromised people were eligible for their first dose of COVID-19 vaccine before the general public, which means they likely got Moderna or Pfizer, which were available sooner in the pandemic.) This week, the CDC issued guidance that Moderna or Pfizer recipients who are moderately or severely immunocompromised may receive a fourth shot or booster at least six months after their third shot. 

When can I get a booster? 

At least two months after your original vaccination, per the recommendation. With the FDA authorization and official CDC recommendation, most pharmacies, clinics and doctor’s offices should be able to give out boosters, depending on what they have in stock, of course. 

Getting an original series of any COVID-19 vaccine remains the best thing people can do to protect against severe COVID-19 disease. Unvaccinated people are more than 10 times more likely to be hospitalized with or die from COVID-19 than fully vaccinated people, according to the CDC. About 20% of US adults haven’t yet received a COVID-19 shot. 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.