Johnson & Johnson pause vaccine trial

It would appear another problem has raised its head in big Pharma’s race to come up with a Covid-19 vaccine.

I recently reported on the halting of the Astra Zeneca’s trial (for a 2nd time) following one of the volunteers in the UK developing an unexplained neurological illness – as a reaction to the vaccine.  The trial resumed 6 days later, although remained on hold in the United States.

This led to some of the volunteers in Spain quitting the Johnson & Johnson trial but the study’s lead researcher reported there were enough “reserve” volunteers for the project to continue.

Now we learn that Johnson & Johnson have had to pause their vaccine trial 

Johnson & Johnson’s Janssen vaccine arm is developing the shot. The company did not say what the unexplained illness was citing patient privacy, but stated one point of clinical trials is to find out if vaccines cause dangerous side effects. Trials are stopped when they pop up while doctors check to see if the illness can be linked to the vaccine or is a coincidence. It is unclear whether the patient received the vaccine or was in the placebo-control group.

The Johnson & Johnson vaccine is known as a recombinant vector vaccine, which uses a modified human common cold virus (adenovirus) that contains the genetic spike protein found in SARS-CoV2, or novel coronavirus

Recombinant vector vaccines are live replicating viruses that are engineered to carry extra genes derived from a pathogen

Live vaccines replicate within the host.  As true of any reproducing population, these within-host vaccine populations may evolve.  For live vaccines that do not transmit, any within-host evolution is a dead end and might thus seem to be irrelevant to vaccine function. But if the process is fast enough, or the vaccine population replicates long enough, the vaccine population may evolve to a state where it is ineffective or virulent—either change would be bad.

The company state “Serious adverse events are not uncommon in clinical trials, and the number of serious adverse events can reasonably be expected to increase in trials involving large numbers of participants, such a pause is not immediately concerning. This is completely expected”.

A careful review of all of the medical information will be undertaken before deciding whether to restart the study”.



I once again re-iterate – researchers have yet to produce a safe and effective vaccine against any coronavirus. 

When researchers were experimenting on vaccines against SARS (similar to COVID-19), trials were halted completely, after the vaccinated animals developed more severe (sometimes fatal) versions of SARS than the unvaccinated animals due to Antibody-Dependent Enhancement (ADE) – (interestingly the animal testing stage has been removed from SARS-Cov-2 trials).  

ADE of infection can be a significant obstacle to the development of safe effective vaccines. The mechanisms of ADE still remain to be better understood.  

I guess the million dollar question has to be would you take an experimental vaccine shrouded in ambiguity about long term health risks or take your chances with Covid-19 which we now know has a survival rate of well over 99% and from which most of us will suffer little or no symptoms at all.

I know my answer, how about you?








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