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The J&J vaccine reportedly confers 85% protection after 1 month. Some suggest this could be improved with a booster. About that...
J&J vaccine uses a replication-incompetent adenovirus (Ad26) to deliver the SARS-2 Spike protein. Here's what a typical adenovirus looks like: (1/5)
J&J vaccine uses a replication-incompetent adenovirus (Ad26) to deliver the SARS-2 Spike protein. Here's what a typical adenovirus looks like: (1/5)
This particular adenovirus, Ad26, was likely chosen as antibody prevalence against it is very low in humans. This allows for the presentation of the SARS-2 Spike protein without the neutralization of the vehicle (Ad26). (2/5) https://jvi.asm.org/content/81/9/4654
Adeno-based vaccines are not new. They can elicit great antibody responses against a custom antigen, like SARS-2 Spike. But they also can elicit an antibody response against the adenovirus itself (esp. true for previous HIV vaccine candidates). (3/5) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3700409/
So a booster of an Adeno-based vaccine might actually be partially neutralized by antibodies made against the original adenovirus. This makes the boosters tricky for them.
Thankfully, the Ad26.SARS.2 from J&J is very good using 1 dose! (4/5)
Thankfully, the Ad26.SARS.2 from J&J is very good using 1 dose! (4/5)
* Moderna/Pfizer vaccines use inert lipid nanoparticles to deliver mRNA encoding for SARS-2 Spike. Since antibodies are not produced against the lipid nanoparticles, a booster works really well! The same can be true for component and live-attenuated vaccines. (5/5)
