There’s been a lot of excitement recently about a Danish study published as a pre-print in the Lancet that analysed trial data and claimed to find adenovirus-vector Covid vaccines such as AstraZeneca (AZ) and Johnson and Johnson (J&J) reduced overall mortality by around 63% and cardiovascular mortality in particular by around 99%. The study authors note it appears these vaccines “provide significant protection” against cardiovascular disease, and speculate this may be because the adenovirus vector, though not able to replicate, “may prime the immune system in a way similar to a ‘live’ vaccine”. How this might protect against cardiovascular disease is not explained.
The study has been reported at sceptical sites such as the Brownstone Institute, TCW Defending Freedom and Bad Cattitude. Each asks whether people have been given the “wrong vaccine”, in that while the trial data for the mRNA vaccines (Pfizer and Moderna) did not show any mortality benefit, those for the adenovirus vaccines showed considerable and, importantly, statistically significant benefit.
I reported on the study earlier in the month, expressing scepticism about the supposed benefits of the adenovirus-vector vaccines for non-Covid mortality.
Medical student Santiago Sanchez has criticised the claims of the study and its commentators on Twitter in a thread that is unnecessarily laced with vitriol but nonetheless makes some helpful points amidst the bile. In particular he notes that almost all the favourable mortality data come from one trial, the J&J one, where nine people in the placebo arm died from non-Covid, non-accident causes versus just three in the vaccine arm (see below).
Indeed, the placebo arm in this trial seems to have been oddly death-prone, with 16 versus three deaths overall, including two versus zero accidents, two versus zero cardiovascular deaths and seven versus three deaths from other causes. Interestingly, the AstraZeneca vaccine trial in the U.S. had an accident-prone vaccine arm, with four versus zero accident deaths, illustrating how these small numbers are very susceptible to freak random occurrences. The same U.S. trial also had two versus zero cardiovascular deaths, while the Sputnik (Gam-COVID-Vac) trial had one versus zero cardiovascular deaths, to give the five versus zero cardiovascular deaths (out of around 50,000 and 72,000 participants respectively) in adenovirus-vector vaccine trials overall that raise the possibility of causation and the vaccines somehow curing heart disease.
Notably, the death rate overall in the adenovirus-vector vaccine trials was considerably lower than in the mRNA vaccine trials (377 vs 822 deaths per million overall, 600 vs 809 per million in just the control arms). This is likely a reflection of the lower age profile of participants in the adenovirus-vector vaccine trials – though this wouldn’t explain the lower proportion of deaths in the vaccine arms versus the control arms.
Perhaps the most significant difference between the two types of trial is in the follow-up time, with the J&J trial follow-up after the single dose being around half that of the mRNA trials after the second dose – and the mRNA trials also had the four week period between the doses.
In the U.S. AZ trial, a massive 10.2% of participants in the vaccine arm (2,206) were followed up for less than 15 days after the second dose (see below). How many of them were lost to follow-up because they died but this was not identified, and how many died subsequently without their death being recorded? It’s worth noting the number lost in the vaccine arm was considerably more than the 8.5% (920) followed up for less than 15 days in the placebo arm.
Santiago Sanchez notes:
If you follow people for longer, more people will die of more causes, by chance. If you look at one group followed over a longer period versus another in a shorter period, you can’t interpret mortality differences between those groups.
Sanchez has also spotted that the recently published final results for the J&J trial are now available and include a longer follow-up time of around four months. By this point the odds ratio (OR) of non-Covid death in the vaccine arm rises to 0.7-1.18 (95% confidence interval), reflecting a between 30% drop and 18% rise, which is not statistically significant. (The final trial data don’t include an update on causes of death so we don’t know how many were cardiovascular.)
Based on this, it seems most unlikely that the adenovirus-vector vaccines really reduce non-Covid mortality or cure heart disease. Much more likely these were random events, assisted by short and possibly weak follow-up.
While adenovirus-vector vaccines may not be as bad for the heart as mRNA vaccines, they have been found to cause some serious and deadly blood clotting issues. More data on vaccines and mortality are needed, but in the meantime it would be advisable to proceed on the basis that any apparent association between the Covid vaccines and improved heart health or reduced non-Covid mortality is coincidental.