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Moderna Announces Results of Phase I clinical trials of mRNA vaccine for COVID-19 (disease caused by SARS-COV-2): Additional vaccines are already in Phase II trials overseas

2020-05-18

Coronavirus by Engin Akyurt via pixabay.com (open access)

Moderna announced results of Phase I clinical trials of a COVID-19 vaccine, resulting in a 700 point rise in the Dow stock market index.  The announcement was carried on all the online news networks as well as print and television.  A total of 45 humans received the vaccine, in three dosages: low, at 25 micrograms, medium, at 100 micrograms, and high, at 250 micrograms of lipid nanoparticles bearing mRNA transcripts for the coronavirus spike protein.  The vaccine was given twice, at two-week intervals, with the first dose given in late March.

Two weeks after the second dose, 8 patients were tested at the low and medium doses for “neutralizing” antibodies (antibodies which were able to stop the virus from infecting human cells in a test tube), and all had sufficient levels.  The antibody levels in four patients who received the 25 mcg dose were described as similar to the levels found in patients who had recovered from the natural illness caused by SARS-COV-2, and antibody levels in four patients who received 100 mcg exceeded those found in natural infection.

According to some media reports, a significant proportion of patients developed fever and other symptoms after receiving the vaccine.  Three out of four patients who received the second 250 mcg dose had grade three (out of four) “systemic” reactions (serious but not “life-threatening”).  Such adverse reactions are typical for vaccines but their frequency is concerning and will probably eliminate the 250 mcg dose from consideration.

Higher frequencies of such “systemic” adverse reactions militate against higher doses of the vaccine, which in turn limit its effectiveness.  However, if a lower dose is settled on finally, more of the vaccine would be available for more patients.

These results clear Moderna to continue on to Phase II of clinical trials.  These trials will be done in a larger group of patients– some 600.  They will determine which dose is optimal for widespread adoption in Phase III, which will begin in July if all goes well in Phase II.  The final phase will determine whether the vaccine is really effective in stopping natural infections and the illness COVID-19 in the wild.

A news release from NIH (the National Institutes of Health) on March 16 announced the commencement of phase I clinical trials for this vaccine, mRNA-1273.  The news release described it as being a fruit of previous research with coronaviruses, specifically the ones which caused SARS and MERS.  The vaccine consists of messenger RNA (mRNA), which is actually the cell’s own normal method for producing proteins; mRNA is translated within the cell into the spike protein of the virus’ envelope with which it attaches to the outside of cells.

The mRNA is enclosed within a lipid nanoparticle; this lipid is like the cell’s own envelope and allows the mRNA to enter a cell.  Injecting this will induce the person’s cells to produce the spike protein, which will in turn stimulate an antibody response.  The antibody will attach to any spike proteins in circulation; if the affected spike protein is attached to a virus the antibody will physically block the virus from invading cells.

When inducing immunity in this fashion, there is always a risk that the presence of circulating spike protein will cause a reaction identical to that which occurs during a natural infection: fever, chills, body-aches, and so on.  The scientists would be surprised if there were not at least some level of “systemic” reaction of this nature.

Due to the exigent circumstances, a greatly accelerated program has been planned which will include a much smaller number of patients than is usually recruited for Phase III studies.  Once Phase III is completed– which will take 6 months– general distribution of the vaccine can begin.  This is planned for January 2021.  I expect that this timetable will be adhered to, for political reasons: the president has promised a vaccine by this date.  Whether the results of the Phase III trials are good or not, the vaccine will be given out as scheduled.

A second vaccine was reported in an NIH release on May 15: a single dose of ChAdOx1 nCoV-19, an investigational vaccine against SARS-CoV-2, has protected six rhesus macaques from pneumonia caused by the virus.  This vaccine was created at the University of Oxford.  Human trials began on April 23.  This vaccine uses a “replication-deficient” (unable to grow) adenovirus to carry a SARS-COV-2 protein, which induces an immune response.  The results were reported on BioRxIv on May 13.

Another report, in Biospace on May 18, states that AstraZeneca will produce 30 million doses of this vaccine for the UK by September and 100 million by the end of the year.  This would represent an example of a vaccine limited to a specific country– a thing that has been deplored by some.

There are over a hundred different vaccines somewhere in the pipeline, but only a total of eight have advanced far enough for clinical trials.  According to Kyodo News on May 16, these eight vaccines include: Inovio in the US, Pfizer and BioNTech SE in Germany, and four in China.  Another six vaccines are in preclinical evaluation in Japan.

Global News of Canada reported that Phase I trials of a Chinese vaccine produced by CanSino Biologics had begun on March 16 and that Phase II trials are underway; further trials in Canada had been approved by Prime Minister Trudeau as of the article’s date, May 16.  The vaccine is called Ad5-nCoV and uses an adenovirus as well, like the one called ChAdOx1 nCoV-19.  According to CTV News, this vaccine could be produced in Canada and China.

Apparently, vaccines of several types could be in use by early next year.  Which vaccines are most successful remains to be seen, but the number of cases worldwide by then will be at least ten and possibly a hundred million.

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