Remember the 'living rapid evidence review' that was monitoring 'The association of smoking status with SARS-CoV-2 infection, hospitalisation and mortality from Covid-19'?
Version 1 was published on April 23, 2020, and thereafter the review was updated at a rate of one a month.
As of January (2021) there had been ten versions of the review whose conclusions I posted here in chronological order.
They were all very similar. According to version 10:
Across 345 studies, recorded current but not past smoking prevalence was generally lower than national prevalence estimates. Current smokers were at reduced risk of testing positive for SARS-CoV-2 and former smokers were at increased risk of hospitalisation, disease severity and mortality compared with never smokers.
Likewise version 11, published on March 2:
Compared with never smokers, current smokers appear to be at reduced risk of SARS-CoV-2 infection while former smokers appear to be at increased risk of hospitalisation, greater disease severity and mortality from COVID-19. However, it is uncertain whether these associations are causal.
Despite that qualification, the conclusions of versions 1-10 were clear and consistent.
Since then however there has been no sign of a further update and I can't help wondering why.
I emailed two of the researchers in June and was told they were aiming for an update in July, 'with v12 available on Qeios in early August'.
It's now August 11 and, so far, nothing.
I don't want to make too much of it because I'm not a conspiracy theorist and I admire the work that has been done to date, but it is a little odd.
If anyone has any information they'd like to share with me, do drop me a note!
Update: The mystery of the missing update has been answered.
Thanks to @Phil_w888 my attention has been drawn to recent tweets by David Simons, one of the four living evidence review researchers, concerning the progress of version 12.
The latest, on August 4, was in response to the question 'Is [v12] online already? Can't find it in Qeios', to which Simons replied:
Not yet. Finalising the last few bits of the write up. Another week or two depending on people's holidays. However, results minimally changed from v11.
I should add that @Phil_w888 has been keeping his own record of pre-prints and peer-reviewed studies concerning the relationship between smoking and Covid-19.
Incredibly the number is fast approaching 4,000 and "the vast majority ... show that people who smoke are less likely to get or be hospitalised with Covid-19".
The evidence, it seems, is indisputable.