As the vaccination campaign in Israel proceeds apace, and now a large chunk of the age 60+ population has had both doses, the public health authorities have released their first preliminary findings on the effectiveness of the vaccine among those who have had both shots and, after one week’s wait, were supposed to be 95% immune. Globes (Israel’s Hebrew-language business paper) has more details than the English-language press. Let me summarize in bullet points:
- of 715,425 vaccinees, just 317 (or 0.04%) tested positive [after 1 or 2 weeks]. For comparison, our daily infection rate in the general population is about 0.1% per day
- of those 317, sixteen (16, or 0.002% of vaccinees) needed hospitalization for COVID
- currently, 322 people under 60 are hospitalized for COVID [note: we do not hospitalize mild and moderate cases for COVID alone, but send them to a “coronahotel” if they are unable to stay at home]. Of these, 83% are unvaccinated, 16% got one dose, and just 1% (to be precise, three patients) had had both doses.
- of the 834 people age 60 and over hospitalized with COVID, 56% was unvaccinated, 42% got one dose, and just 13 people (rounds up to 2%) had had both doses. It is unclear whether some of these were already infected before they got the second shot: the first shot on its own is only expected to be about 50% effective. It is also not clear whether some of the others have immunodeficiencies.
- At present, about 65% of people 60 and older have had both shots, but the relevant situation is probably that of a week or more ago with, say, 20-30% coverage. So it would seem that we are looking at about 90% effectiveness or better.
- In the Pfizer clinical trial, nobody of the about 15,000 vaccinated got seriously ill — while the above statistics (on about 50x the number of people) do indicate that it is possible, albeit rare
- There are indications the vaccination campaign is already affecting serious morbidity, with a significant drop in hospitalized patients expected to start next week
- The British variant now accounts for 60% of new cases; fortunately it does not appear to be an ‘escape mutation’ (term I learned from my virologist colleagues) and the vaccine appears to be effective against it. The jury is out on whether this will be the case for the South African mutation.
Obviously, we will need a longer time interval for the data to firm up, but so far things are looking good for the Pfizer vaccine. (We also have a small supply of the Moderna mRNA vaccine, which is used for in-home vaccination of elderly people who cannot make the trip to the vaccination sites. The reason: Moderna has more lenient freezing/cooling requirements and is hence more suitable to be transported in a doctor or nurse’s car or bag.) In all, this is an unofficial Phase IV trial on a massive scale. Check back here for further developments.
If an escape mutation necessitates a ‘reprogramming’ of the vaccine and a new vaccination drive, does this require a whole new FDA approval process, clinical trials and all? An insider told me that seasonal flu vaccines probably have established a precedent for the contrary, as it is impossible to make a selection of strains and run a whole new set of clinical trials every year — by the time they are finished and you can mass-manufacture, flu season is likely over.
UPDATE: Times of Israel reports data from the Maccabi HMO [*] that also include a proper control population:
Pfizer’s coronavirus vaccine is showing 92 percent effectiveness in Israel, according to the world’s first big controlled investigation on how it works outside of clinical tests. / Only 31 out of 163,000 Israelis vaccinated by Maccabi Healthcare Services caught coronavirus in their first 10 days of full-strength protection, its top vaccine statistics analyst, Anat Ekka Zohar, told The Times of Israel on Thursday. / In an equivalent sample of unvaccinated Israelis, some 6,437 were diagnosed in the same timeframe. […]
Maccabi has analyzed a control group of Israelis with similar age and health profiles [as the] vaccinees, composed entirely of people [who] haven’t been [previously] infected or received shots. This allowed Maccabi to calculate its real-world effectiveness rate. […] Ekka Zohar said she was encouraged by the light symptoms of vaccinated people who caught the coronavirus, as well as by the low infection rates. “None have been hospitalized and they have very very light symptoms,” she stated. “We are talking about headache and a mild feeling of sickness, and they are almost completely without fever. It’s really a very light illness.” […]The Health Ministry reported that there have been 317 infections among 715,425 vaccinees, a rate of 0.044%, or about double the infection rate seen among Maccabi members. However, Maccabi members tend to come from a higher socioeconomic background and live in areas with low infection levels. Ekka Zohar said that if there were a national control group, it would likely indicate a similar effectiveness level to Maccabi’s data.
And in tangentially related news, the origin theory of COVID19 as an accidental leak from a lab engaged in “gain of function” research just went from “only conspiracy theorists believe this” to… being endorsed by a WHO advisor and former Clinton and Biden staffer, Jamie Metzl, in an interview in the Toronto Sun. Wow.
[*] All Israelis by law have to belong to one of the four licensed HMOs [you can switch every six months if you so desire]: Clalit [the largest, historically an arm of the Histadrut trade union federation], Maccabi [historically the HMO of self-employed professionals and well-off people], Meuchedet [“United”, a merger of two smaller HMOs], and the small Leumit [“Nationalist”]. Full disclosure: our family is enrolled in Maccabi, though we carry supplemental private insurance.