I’m struggling to find information on this, but is there any protection offered after receiving the first dose of a two-part series? I feel like there would be some protection, with possibly an exposure after that time kinda helping kick the immune system into gear similar to how the second dose would, but that’s just a hunch and not actually based on anything. Anyone know if there’s anything on that out there, or have enough expertise to extrapolate?
I wondered the same thing. It sounds like they don’t know yet when I went digging for it.
Data Point: The Shingles Vaccine is estimated to be about 70% effective after the first dose.
From the Washington Post:
“For all we know, all these two-dose vaccines may work in one dose,” Duchin said.
“There are a lot of missing data points,” said John Brownstein,
The challenges of registering individuals and reminding them electronically about their second shots are daunting,
Moore, who has studied another painful vaccine — two-dose shingles shots — says she is heartened by the way a vast majority of people who are educated about what to expect come back for their second doses despite the discomfort.
It’s probably safe to say there’s some immunity after the first dose but because there’s only a month between shots in the trials it’s not really usefully measurable at this point. The way they’re measuring efficacy is number of people infected in active group v placebo so far. For the numbers you’re looking for we’d have to look at just that month long interval between shots. I doubt enough people got infected in that one month to do proper stats on.
I keep seeing articles that say things like 30 million doses by the end of December is enough to vaccinate 15 million people, but if it’s 70% effective after one dose does it really make sense to only use 1/2 of the initial batch and then hold onto the other half a month (or perhaps more literally reserve a second dose for person X given it can’t all be distributed in a day,) instead of giving 30 million people dose 1 and using the next batch to give them dose 2?
I have a piggyback question: After you get the first dose, is a second dose earmarked for you? In other words, if I get dose today, do I have to worry about the supply running out in a month and not being able to get the second one until it’s restocked or is it more along the lines of when they say they have 50m doses, they mean they can give 50 million (or 25 million) both shots?
I don’t know for this vax, but I know my 2nd Shingrix dose was set aside for me.
This was a question that came up during one of last week’s press conferences with DeWine. He said that they didn’t have to reserve half of the supply they were getting for second doses, he said in his conversations with Pence, the government and/or the vaccine manufacturers were already considering that in what they were releasing
They are saying that the 2nd dose is earmarked for you.
They’re trying to plan out ahead of time what to do with the second dose if the person doesn’t show up for it.
That’s good to know. I don’t know what happens if you go longer between doses (6 months? a year?) but it seems like it’s not going to be an issue for most people.
The clinical data also suggest that the vaccine may be able to prevent COVID-19 after the first dose — 82% effective — though the FDA analysis says the available information doesn’t allow for a firm conclusion on that potential effect.
I heard that NPR report this morning, and they raised an interesting question. In a public health emergency, with limited number of doses available, if one dose has a greater than 80% effectiveness, should we just give everyone (or some subset of everyone) one dose?
That would double or nearly double the number of doses available, getting more people vaccinated at a pretty darn good rate of effectiveness quickly. Is it better to get half the people vaccinated for just a marginally better effectiveness rate? or double the numbers?
No, there will be more being produced. You need to have the double dose for the longer term and much higher protection. Better to get 20 million medical workers and the most vulnerable very protected than give 40 million a shorter term and much lesser protection.
This NYT article describes a study indicating the Pfizer vaccine is about 52% effective 10 days after the first dose (and 95% effective after the second), though it’s not clear how long immunity from just one dose would last. https://www.nytimes.com/2020/12/08/health/covid-vaccine-pfizer.html?referringSource=articleShare
Would it be a flat 80%, or would it be whatever is required for herd immunity for that illness? Measles requires 95% for herd immunity, because it is so contagious, but there are other illnesses whose vaccine reaches herd immunity at 70% (I don’t recall which), because the diseases are not very easily passed on.
There’s really no way to know at this point at all.
This graph was interesting. It seems like after about 10-12 days the first dose of the vaccine was starting to have some effect.
Right. That’s the result of getting it out in under a year. Don’t get me wrong; that’s not a criticism. I think they did a wonderful job, but there is a lot they don’t know.
Are the two doses exactly the same?
The plan is for you to get two doses from the same batch, both being the same dosage. So yes.