COVID19 update, May 24, 2020: vaccine trails hampered by dwindling infections; phases in clinical trials; miscellaneous updates

(1) The Daily Telegraph reports that the Oxford/AstraZeneca vaccine trial is now running into an unexpected snag.

At present a Phase 2 trial is underway with 10,000 volunteers, half of whom get the vaccine, the other half a placebo. The idea is to compare the infection rates between the two groups in order to find out whether the vaccine does indeed have protective value.

But currently infections in the UK are falling to the point that simply not enough people may get infected to be able to learn anything from the trial.

(As related here previously, an earlier vaccine for the original SARS, developed by Janssen Pharmaceutica, was never taken into production because the epidemic died out before human trials could be completed.)

According to the Telegraph, three Chinese groups are running into a similar problem with their respective vaccine candidates.

A “plan B” that nobody dares to suggest would be a “challenge trial”. Here, a smaller group of volunteers would agree to be deliberately infected with the virus 2-3 weeks after vaccination. (Here a placebo control group would presumably be unnecessary.) Healthcare workers dealing with COVID19 patients would be another option for a challenge trial, as these would already run plenty of risk of infection. (The cynical mind wonders about recruiting volunteers for a challenge trial among the ChiCom regime fanboys one encounters in academia and the media.)

The Telegraph also addresses earlier reports that rhesus monkeys subjected to a similar challenge trial did shed viral particles from their nose at similar rates as unvaccinated monkeys. Lead developer, Prof. Adrian Hill, however waves this away, as “the monkeys had been deliberately “overdosed” on coronavirus in order to test for safety.”

“We used a really high dose and these guys gave it not just into the lungs and the nose. They gave it into the mouth, and they gave it into the eyes. They gave a huge dose. I mean, seriously, it’s that level of basic.”

UPDATE: Dr. John Campbell on recent vaccine trials

(2) What’s the deal with “Phases” in clinical trials actually? According to definitions are as follows

* Phase 0 (a.k.a. Early Phase 1): exploratory trials with microbuses to investigate how or whether a drug interacts with the body.

* Phase 1: safety testing. “They are usually conducted with healthy volunteers, and the goal is to determine the drug’s most frequent and serious adverse events and, often, how the drug is broken down and excreted by the body. These trials usually involve a small number of participants.”

* Phase 2: effectiveness testing. The drug is tested on people who have the condition/disease that it is meant to cure or mitigate. There is almost always a control arm comparable in size and composition: patients in the control arm may receive either a placebo or (where there is one) the current “drug of choice’. Any adverse effects are monitored.

If the drug is found to have a statistically significant ‘therapeutic advantage’, then testing proceeds to 

* Phase 3: “A phase of research to describe clinical trials that gather more information about a drug’s safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs. These studies typically involve more participants.”

If the drug passes that stage and gets approved by the FDA and/or its foreign counterparts, it goes to market. Any post-approval studies may be labeled Phase 4.

What if you have an unproven drug that might save a dying patient’s life, and no better option is available? Then a ‘compassionate use exemption’ applies, provided the patient, a licensed physician, and the drug manufacturer are all willing to try this ‘Hail Mary pass’, since the patient is otherwise doomed anyway. A treatment protocol is to be submitted to the FDA. A less formal version is how our first COVID19 cure (“patient #19”) with remdesivir came about.

Now when testing a drug, elaborate and costly as it may be, at least you have a population of patients already sick. With a vaccine candidate you have additional complications.

* You give vaccines to lots of healthy people, and the first rule of the Hippocratic oath (or its Jewish counterpart, the Oath of Assaf the Physician) is primum non nocere/above all, do no harm. 

* Normally, unless (see above) a challenge trial is set up, only a smaller or larger minority of vaccinated people will be exposed to the pathogen. That means that the sample sizes for phase 2 and 3 clinical trials need to be much larger than for a drug.

(3) Some links, you decide

* via David Bernstein, a piece in the Salt Lake Tribune (archive copy here, especially as the SLTrib is not accessible in Europe ) about some probable and unlikely infection scenario’s.  

* Michael Levitt, 2013 Nobel laureate in Chemistry, in an interview in the Daily Telegraph argues that lockdowns did not result in net saved lives and may indeed have had a net cost. I think he oversells his case, but let the man have his say and make up your own mind.

* an anecdotal data point: a woman who has been taking hydroxychloroquine for 19 years to mitigate her lupus now contracted COVID19 regardless, and predictably blames…

* hat-tip to Lissa Halley, a study tracing 455 contacts of an asymptomatic carrier (who was hospitalized for an unrelated chronic heart issue) revealed no infections among any contacts. I would like to see further confirmation, as zero infections out of 455 sounds almost too good to be true.

One thought on “COVID19 update, May 24, 2020: vaccine trails hampered by dwindling infections; phases in clinical trials; miscellaneous updates

  1. Things are getting interesting… And I’m not sure we’re actually any closer to a vaccine or a valid treatment that will satisfy the ‘scientists’…

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