The Johnson & Johnson COVID-19 Vaccine: A Gamechanger?

Author: Ivana Mišová, PhD.

Published at: 03/16/2021

Recently, a new COVID-19 vaccine produced by Johnson & Johnson has entered the market. What do we know about it, and how does it impact the vaccination plan? 

The novel vaccine developed by the Janssen Pharmaceutical Companies of Johnson & Johnson is commonly referred to as the Janssen COVID-19 vaccine or the Johnson & Johnson COVID-19 vaccine. In research articles, it is called Ad26.COV2.S, based on its character as a recombinant, replication-incompetent adenovirus serotype 26 (Ad26) vector encoding a full-length and stabilized SARS-CoV-2 spike protein1. Thus, the Janssen COVID-19 vaccine is more similar to the AstraZeneca or Sputnik V vaccines, which are also viral vector-based vaccines. However, unlike any other vaccines on the global market, it is a single-shot vaccine2.

So how does the Janssen COVID-19 vaccine fare compared to other vaccines on the market? Based on the Phase 3 ENSEMBLE study to evaluate the vaccine's safety and efficacy, the vaccine was 85% effective in preventing severe disease across all regions studied and showed protection against COVID-19 related hospitalization and death, beginning 28 days after vaccination2. 14 days after the first (and only!) vaccination, the vaccine is already 77% effective in preventing severe/critical COVID-19. While the efficacy is a bit lower than the efficacy of the Pfizer or Moderna vaccines (read more), a key fact is that this study was conducted across three continents, including countries such as Brazil and South Africa that have different dominant strains of the coronavirus (read more)3. In particular, in South Africa (with 84.5% of strains identified as the B.1.351 lineage), the vaccine's efficacy at least 28 days post-vaccination was 64% against moderate to severe COVID-19 and 73.1% against severe/critical COVID-19. The company is also testing a two-dose regimen in the ENSEMBLE 2 study to see if a second dose of the vaccine might provide greater or longer protection4. Moreover, about 34% of people included in the clinical study were older than 60 years3 - a significant difference from the AstraZeneca vaccine, which has age limits in multiple countries due to insufficient clinical trial data on their efficacy in the elderly population. 

A great advantage of the Janssen COVID-19 vaccine is its storage and distribution conditions. This vaccine is compatible with standard vaccine storage - stable for two years at -20°C (-4°F) and three months at routine refrigeration at 2°C to 8°C (36°F - 46°F)3. These conditions are typical for viral vector-based vaccines and much easier to comply with than the requirements of mRNA vaccines such as the Pfizer or Moderna vaccine. 

Regarding the cost of the vaccine, Johnson & Johnson is committed to making its COVID-19 vaccine available on a not-for-profit basis for emergency pandemic use5. The company will provide up to 500 million doses of its COVID-19 vaccine as part of an agreement with The Vaccine Alliance Gavi - the organization responsible for equitable access to vaccines and coordination of procurement and distribution of COVID-19 vaccines via the COVAX Facility6

The vaccine is currently approved in many countries. On February 27, 2021, the Janssen COVID-19 vaccine received emergency use authorization from the U.S. FDA7. On March 5, 2021, it was approved in Canada8. Just a few day later, on March 11, 2021, the vaccine was granted conditional marketing authorization by the European Medicines Agency, making it available in the EU9.

The approval of the Janssen COVID-19 vaccine is great news. First, any effective vaccine's approval dramatically augments the number of available vaccines, making the vaccination process much faster. To stop the coronavirus spread, the goal is to have enough people vaccinated against COVID-19 to achieve herd immunity. With a single-dose vaccine, the time necessary for acquiring immunity is significantly lower. Taken together, the arrival of the single-shot Janssen COVID-19 vaccine on the market is a wonderful thing in view of the current pandemic. 


  1. Sadoff, J., Le Gars, M., Shukarev, G., Heerwegh, D., Truyers, C., de Groot, A. M., Stoop, J., Tete, S., Van Damme, W., Leroux-Roels, I., Berghmans, P. J., Kimmel, M., Van Damme, P., de Hoon, J., Smith, W., Stephenson, K. E., De Rosa, S. C., Cohen, K. W., McElrath, M. J., Cormier, E., … Schuitemaker, H. (2021). Interim Results of a Phase 1-2a Trial of Ad26.COV2.S Covid-19 Vaccine. The New England journal of medicine, NEJMoa2034201. Advance online publication.