Information adapted from

Johnson and Johnson may be the next vaccine to be released to the public.  There are some critical differences between Johnson and Johnson’s COVID-19 vaccine and the current offerings of Pfizer and Moderna.  Comparing some of their strengths and weaknesses can help consumers make informed decisions about vaccination.

J&J is “One and Done”

One of the biggest strengths with the Johnson and Johnson shot is that will be easier for mass vaccination, as it only requires one shot.  This is in comparison to Pfizer and Moderna, which both require a series of two shots.  Any vaccination that requires multiple injections has the risk of patients forgetting or not wanting their second dose, resulting in an incomplete series and reduced effectiveness.  The vaccine also does not require ultra-cold storage (like Pfizer), making it very user-friendly for clinicians.

Adenovector Tech

Both Pfizer and Moderna are effective by using mRNA to produce an immune response.  Johnson and Johnson, however uses adenovectors, which are modified adenoviruses that have been rendered harmless (note: normal adenoviruses produce mild colds, much less severe than COVID-19).  This adenovector is modified with the spike protein of SARS CoV2 (the virus that causes COVID-19), thus able to initiate the immune system’s response of replicating antibodies against COVID-19.  This technology is not new, and is actually quite similar to Ebola vaccines also developed by Johnson and Johnson.


Another major difference, one that has sparked a lot of concern, is the reduced effectiveness of the Johnson and Johnson vaccine.  Pfizer and Moderna vaccines have 95% and 94.1% effectiveness, respectively, which is a success rate that far surpasses many common vaccines, even the annual flu shot.  Johnson and Johnson’s vaccine, however,  has an overall  66% in preventing COVID-19.  As low as that may be compared to the other two vaccines, this is still a promising number.  The vaccine is up to 85% effective in preventing serious complications due to COVID-19, making it a viable candidate for use.  And just like Pfizer and Moderna, the Johnson and Johnson vaccine has gone through rigorous human trials and will continue to do so during and after its release to the public.


As the situation evolves around vaccination, McDonough County ESDA aims to keep you informed around the latest scientific breakthroughs, and what they mean for our community.  Johnson and Johnson’s vaccine may be the next vaccine to reach our locality, and we look forward to its availability to the public.