Vaccines are effective at protecting one from serious illness or hospitalization if COVID-19 is contracted. They are not perfect, but they are useful tools in preventing severe disease or death.
Almost one million Americans have reportedly succumbed to COVID-19 with many of those being underprivileged and underserved. As the pandemic goes into its third year, more data exists to analyze.
Mask mandates have changed to recommendations, and those recommendations vary based on the number of reported cases. Vaccines, unlike masks, were never mandated, but recommended.
The initial vaccine rollout was hampered by availability, and three products were offered in the USA—two mRNA-based vaccines, Pfizer and Moderna, and one adenovirus vector-based vaccine, Johnson & Johnson (J&J). The least used vaccine, the J&J product, has the least amount of published guidance.
J&J pros and cons
Recall that the J&J vaccine utilizes the adenovirus vector to train the immune system. It was popular as only one dose was presumed, and it was easier to transport than the mRNA-based vaccines.
Analysis of current data showed the J&J vaccine offered less protection in regards to hospitalization or death as compared to mRNA-based vaccines. Additionally, an advisory was released regarding a rare blood clotting syndrome known as thrombosis with thrombocytopenia (low platelets) syndrome or TTS.
Eighteen million doses of J&J were administered, but 57 cases of TTS were reported as of December 2021. Thirty-six of the 56 cases required intensive care management.
Although the J&J vaccine provides a lower level of initial protection than the messenger RNA vaccines, the company has pointed to evidence that its vaccine’s protection may not erode as quickly. They funded a study and published it in the Journal of American Medical Association Network and found that vaccine effectiveness was stable over six months. It was 81% effective at preventing hospitalization, although this number was calculated before the omicron variant’s emergence.
As time went on it was apparent that the effectiveness of the J&J vaccine waned as serum (blood) antibody levels fell after eight weeks. A second dose was needed to maintain effectiveness, thus a booster was recommended. The choice of boosting is referred to staying “up to date” with one’s vaccinations.
The CDC still considers one fully vaccinated after one dose of J&J. If an individual did develop TTS after one dose of J&J, the FDA contraindicated provision of a second dose.
Current evidence guided the CDC into recommending Moderna or Pfizer if available for initial vaccination versus J&J. The majority of primary J&J recipients who choose a booster have been utilizing the mRNA-based vaccines.
When to consider J&J
The current CDC position recommends individuals consider J&J under the following circumstances:
- Had a severe reaction after an mRNA vaccine dose or have a severe allergy to an ingredient of Pfizer-BioNTech or Moderna (mRNA COVID-19 vaccines);
- Would otherwise remain unvaccinated for COVID-19 due to limited access to Pfizer-BioNTech or Moderna (mRNA COVID-19 vaccines); or
- Want to get the J&J/Janssen COVID-19 vaccine despite the safety concerns.
Currently, omicron is the predominant variant, and a study based on data from 10 states from mid-December 2021 to early March 7, 2022, demonstrated J&J prevented COVID-19-based hospitalization.
- One dose was 31% effective.
- Two doses were 67% effective.
- One dose of the J&J vaccine plus one dose of an mRNA booster were 78% effective.
In comparison, three doses of any mRNA vaccine provided 90% effectiveness at preventing hospitalization.
People who have J&J fall into these categories:
- One dose of J&J vaccination = Primary dose and are considered fully vaccinated
- Primary and Boosted (with a second dose of J&J)
- Primary and mRNA booster = Recommended choice by CDC as of now.
Most effective dosage
Any of the above scenarios can help prevent COVID-19-based hospitalization, but the most effective is the third option per the current data. J&J vaccination has been reported to induce a greater response of cytotoxic T cell activation, even though antibody levels to Sars-CoV-2 fall in comparison to mRNA vaccinated individuals.
The T cell activation by J&J may continue to provide stable protection beyond what the mRNA vaccines do. This durability of immune response could provide some sort of longer-lasting protection.
The recommendations will evolve as time goes on and more data is available. As always, consult with your healthcare provider to plan a strategy that is best for you.
Sean J. Ennevor, M.D. graduated with a B.A.S. in biology and economics from Stanford University, and as a Dean’s Scholar from UCLA School of Medicine where he received his MD. He completed his medical residency and fellowship in anesthesiology at Yale University, where he was chief resident and on staff. He practiced medicine in the Twin Cities for over 14 years, and presently serves as an advisor and investor for medical technology companies throughout the country.