Regarding the NIH article you cited "Is One Vaccine Dose Enough After COVID-19 Infection?", the referenced study referred to people who tested positive for antibodies prior to getting the vaccine. This is just a subset of those people that were infected with COVID-19, and the article should have been more clear on this point.
The article raises the question of whether there is any substantive benefit to getting the second shot for those that tested positive for antibodies prior to getting the first shot. Two related questions then arise:
1. Is there any harm to giving the second shot to people that tested positive for antibodies prior to getting the first shot?
2. Is there any similar benefit/harm to people that recovered from COVID-19 but no longer test positive for antibodies?
These are good questions, Robert. I do not know if I can reasonably answer them both. For (1), it is easy enough to say that one harm is having to have any potential safety events from the second dose of vaccine. Although they are few, they are still something that would be nice to be able to avoid. In the meantime, we also need to consider that if we reduced the number of shots required to vaccinate an antibody-positive person, we would free up those second doses for use in other people. So there is also a wider potential harm in terms of the supply crunch. Every two people who we don't have to vaccinate a second time leads to one more person who can get a full course--or two more people, if those additional two are also antibody-positive. So that's a substantial gain we'd be walking away from.
(2) I can't speak to this situation because I don't know of any data in such people looking at this. However, if they have an equivalent experience to those who have detectable antibody levels and thus require only 1 dose to be protected, then the answer to (1) applies. If such people without detectable antibodies are not able to get protection through 1 dose only, then the question is sort of trivial--obviously they would benefit more from 2 doses than 1.
Regarding the NIH article you cited "Is One Vaccine Dose Enough After COVID-19 Infection?", the referenced study referred to people who tested positive for antibodies prior to getting the vaccine. This is just a subset of those people that were infected with COVID-19, and the article should have been more clear on this point.
The article raises the question of whether there is any substantive benefit to getting the second shot for those that tested positive for antibodies prior to getting the first shot. Two related questions then arise:
1. Is there any harm to giving the second shot to people that tested positive for antibodies prior to getting the first shot?
2. Is there any similar benefit/harm to people that recovered from COVID-19 but no longer test positive for antibodies?
These are good questions, Robert. I do not know if I can reasonably answer them both. For (1), it is easy enough to say that one harm is having to have any potential safety events from the second dose of vaccine. Although they are few, they are still something that would be nice to be able to avoid. In the meantime, we also need to consider that if we reduced the number of shots required to vaccinate an antibody-positive person, we would free up those second doses for use in other people. So there is also a wider potential harm in terms of the supply crunch. Every two people who we don't have to vaccinate a second time leads to one more person who can get a full course--or two more people, if those additional two are also antibody-positive. So that's a substantial gain we'd be walking away from.
(2) I can't speak to this situation because I don't know of any data in such people looking at this. However, if they have an equivalent experience to those who have detectable antibody levels and thus require only 1 dose to be protected, then the answer to (1) applies. If such people without detectable antibodies are not able to get protection through 1 dose only, then the question is sort of trivial--obviously they would benefit more from 2 doses than 1.