The second reference does not provide a citation for the "39% efficiency against infection" claim. But some digging turned up the Israeli Ministry of Health press release from May [1], which states:
- "From the epidemiological analysis by public health services in the Ministry of Health, it is evident that since June 6th there was marked decline in the effectiveness of the vaccine in preventing infection (64%) and symptomatic illness (64%)."
In summary [1] also does not support the "6.72 times more likely to get infected" claim. And since the data backing [1] does not appear to be publicly available nor subject to any peer-review process or other academic scrutiny, it should be taken with a big grain of salt.
I personally wouldn't dismiss these numbers, given they are the best we have at the moment. I expect more data to come.
I'm personally not surprised that natural immunity on average is better, given that not just the spike protein is targeted. I had hoped that the vaccine immunity would have lasted longer.
(I still assume that vaccines will continue to be a great help along the way until covid is endemic like the several other coronaviruses in circulation.)
Those preliminary are consistent with this study which found the same low risk of reinfection [0]:
> the estimated risk was low (0.1% [95% CI: 0.08-0.11%]) with no evidence of waning immunity for up to 7 months following primary infection.
Also there's this, indicating the vaccine may not be as effective as time goes on [1]:
> Researchers at the Ministry of Health took another look at the effectiveness of the vaccine, limiting their analysis to the surge from June 6 to July 3. In that period, they estimated, the effectiveness of the vaccine at preventing infections was down to 64 percent.
> More recently, they ran another analysis. This time, they looked at cases between June 20 and July 17. In that period, they estimated, the vaccine’s effectiveness was even lower: just 39 percent against infection.
Not a published study, but I assume that the Israeli Ministry of Health is not making up numbers.
Are there any published studies to the contrary? These are the numbers we have at the moment. I assume more will come, from the U.K. where they are also tracking stuff like this better than in the U.S.
[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8209951/pdf/RMV...
[1] https://www.nytimes.com/2021/07/23/science/covid-vaccine-isr...