So, you're saying that an orally or nasally administered vaccine would be more effective against a respiratory virus than a shot in the arm or to the backside? Wouldn't the circulatory system make all the virion particles available to the immune system no matter where they entered the body? And vice-versa, wouldn't the circulatory system make all the manufactured antibodies available to any tissues in the body where antigens may be present?
Nasal spray would be the best. No. The effectiveness of the vaccine suffers when it is injected into a didtant site, Secretory IgA is needed, not circulatory.
So, you're saying that an orally or nasally administered vaccine would be more effective against a respiratory virus than a shot in the arm or to the backside? Wouldn't the circulatory system make all the virion particles available to the immune system no matter where they entered the body? And vice-versa, wouldn't the circulatory system make all the manufactured antibodies available to any tissues in the body where antigens may be present?
Nasal spray would be the best. No. The effectiveness of the vaccine suffers when it is injected into a didtant site, Secretory IgA is needed, not circulatory.