This is of course exactly what was expected, and why First Dose First was so clearly the right strategy until countries had plenty of supply. Good for the UK recognizing this early. The US hasn't.
A few months ago I remember there were interviews and articles with immunologists and virologists. There seemed to be a consistent sentiment with many of them at least that the Pfizer and Moderna protocol intervals were kind of suboptimal from an immunology perspective. The conclusion was that many in the field saw it as obvious that the two companies were trying to maximize the probability of vaccine efficacy in as short of period of time as possible (I don't think they saw the companies as acting immorally, just that they saw it as not making sense unless you understood the time constraints). Many of the people interviewed commented that with unlimited time and lack of public health constraints, they would have expected smaller doses given longer apart.
I guess my point is, I'm not an expert in this area but there was a lot of chatter earlier that this was kind of predictable or something.
That would be unexpected. Not impossible, but improbable. Think about it this way: do you know of any other vaccines with 4-week intervals? If all other vaccines use longer intervals, what are the chances that this particular vaccines needs a shorter interval?
The decisions made in UK and Canada to delay the second dose were not a random choice. They were expected to work based on the body of knowledge we have from other vaccines and what we know about the immune system. It was by no means a certainty, but a strong probability. And it paid off.
For children receiving their first vaccines for the flu (whether inactivated or live), it is recommended they receive two doses 4 weeks apart.
Lots of the early childhood vaccines have minimum spacings of 4 weeks, but are given at 2, 4, and 6 months simply because of standard pediatric followup visit schedules: DTaP, Hib, IPV, PCV13, and Rotavirus. HepB has a first dose at birth and the second at 4 weeks -- 2 months.
HPV is available in a 3-dose series with 4 weeks between the first two doses.
Even Bexsero vaccine has recommended interval of at least 1 months or 2 months, not exactly one month or at most 1 month. It seems to be consistent with longer intervals being ok.
The human trials had already shown that just one dose of Pfizer has an efficacy of 89% after 15 days. With a fast-spreading pandemic, the priority is to get as many people on their first dose as possible. This both starts to reduce the rate of infection, and also reduces the death rate.
The long-term effectiveness isn't a priority at first for the most developed countries. If necessary they can just order more vaccine after a few months and run a booster campaign later in the year. Cost isn't an issue.
> Two doses of the Pfizer vaccine had an effectiveness of 93.7% at preventing symptomatic alpha infections, and 88% for the delta variant.
[..]
> However, the effectiveness of the vaccines plummeted if a patient had only received one dose of either vaccine: the study found both to be just more than 48% effective against alpha and only about 30% effective against delta.
I'm a little confused as to what your point is? The vaccines are highly effective after two doses, but not very effective after only one dose.
50% (48%) is for Alpha (I'm actually a little surprised it's that low; IIRC it was a lot better in the initial studies, though those were on the ancestral variant, not Alpha). For Delta, it's 30%, per that article. I'd call that pretty low.
That said, other studies are available, and some have shown decent performance against Delta after one dose.
This is easy to say if one is living in the country with all the vaccine supply. Canada bought more doses per capita than any other country, yet US prohibitions on vaccine export meant Canada could not get enough supply in the first few months of the vaccine rollout. A calculated risk was taken to give first doses while waiting for supply to come online, which did eventually happen.
This was not some random experiment on the population. While the gold standard of a phase three trial was not available to support the longer interval, there was plenty of data about the performance of prior vaccines, and interim data about immunogenicity with a longer interval for the COVID-19 vaccines.
No. It is ethical to do that which maximizes life-saving outcomes. Saying that something is an "untested medical intervention" lacks the nuance of saying that some interventions are completely unknown, while others have fairly predictable and understandable effects.
The effects of a single dose were reasonably well understood as well as the impacts on transmission. Reducing transmission is a potentially more relevant goal than individual health outcomes in the grand scheme of things.
While I agree with you on the overall sentiment, it is very hard to apply sometimes. Here in Germany there were a lot of calls to start handing out Curevac doses. They had a few million ready to go, but we were still awaiting trial data.
Our government decided against the emergency usage in the end, and it was the right decision in hindsight, as it turns out that the vaccine is far less effective than its competitors, and could very well have had similar problems as AZ or Biontech.
No one ever claimed that it was the best option, just that it was the only option clinically tested. It would have been irresponsible to recommend a different option without at least some limited clinical trials. Sometimes you can't wait for perfect data.
