Story at a glance
- The Johnson & Johnson is a safe and effective vaccine against the coronavirus.
- Data suggests that it may be less effective than mRNA vaccines from Pfizer/BioNTech and Moderna, but it may have lasting and durable effectiveness, according to a new study.
- A study from the CDC finds that a J&J vaccine with an mRNA booster shot was more effective than two J&J shots at preventing hospitalizations during the recent omicron wave.
The Johnson & Johnson coronavirus vaccine, also known as the Janssen vaccine, is recommended as a single shot, but booster dose is two months later, according to the Centers for Disease Control and Prevention (CDC). Overall, the vaccine efficacy for the Janssen vaccine seems to be lower than for the mRNA vaccines from Pfizer/BioNTech and Moderna. Recent studies have added to the understanding of the vaccine’s durability and recommended booster shots.
Several studies on efficacy against severe COVID-19, hospitalizations and deaths find that one Janssen dose is less effective than two doses of either mRNA vaccine. This has been noted and suspected by health officials since last year. However, these studies only include one Janssen dose, and not the booster dose two months later. They were also conducted prior to the emergence of the omicron variant.
Newer studies on durability of vaccine efficacy and booster shot combinations are adding to what we know. A study uploaded to a preprint server in January suggests that is waning protection against hospitalization in the Pfizer/BioNTech and Moderna vaccines at the five month mark post-vaccination, but no evidence of waning protection from the Janssen vaccine.
Protection against infections started waning in month two for people who received either the Pfizer/BioNTech or Moderna vaccines. For the Janssen vaccine, protection against infection started to dip after month four.
Protection against hospitalizations started dropping for the Pfizer/BioNTech vaccine in the second month, and for Moderna in the third month. The research also suggests protection against intensive care unit admissions stays the same for all three vaccines.
However, there are some limitations with the study. The data are from Jan. 1 to Sept. 7, 2021, so it does not consider whether people were exposed to newer variants of omicron. This study has not yet gone through the peer review process for publication in an academic journal, so the results should be taken with a grain of salt.
This week, the CDC released a study on effectiveness of pairing a Janssen primary dose with a Janssen booster dose compared to mRNA booster doses. During the omicron wave, people who received a Janssen dose and an mRNA booster had higher protection against hospitalizations than people who got two Janssen doses. The authors of the study include the caveat that the median time from the most recent dose to a medical event was between 48 and 59 days and the maximum was 120 days. So this study does not account for waning protection or considerations of durability of vaccine efficacy. They also had a small number of Janssen recipients and that could mean that we’re not seeing the full picture.
The CDC recommends that people who got a primary dose of the Janssen vaccine follow with a booster dose of an mRNA vaccine at least two months later, or get a booster dose of the Janssen vaccine if other vaccines are unavailable or they are unable to get an mRNA vaccine for any other reason.
Published on Mar. 31, 2022