4 ms·

so how are the first and the second dose different?

• meepmorp 6y ago
  They're the same. It's just a second dose as a booster.
• hfjfktmtkrn 6y ago
  The second dose is like seeing someone stalking you for the second time. You should really do something about it because it's probably serious. The same way, the immune system gets really triggered when it sees the same thing which it supposedly cleared at a later date.
• jonbaer 6y ago
  "Some vaccines require two doses because the immune response to the first dose is rather weak. The second dose helps to better reinforce this immune response." - I would have to think over time that could be optimized somehow to just require one w/ ML and test results, etc.
• takeda 6y ago
  I believe only Sputnik vaccine has different first and second dose, but their vaccine is of different category (it belongs to the same as AstraZeneca and Johnson and Johnson). The reason is that these vaccine use a vector (adenovirus) and there's a risk that body will develop antibodies for the vector and the second dose might not be as effective.