A belated and somewhat bitty update, due to illness over the past week (respiratory, although thankfully ticking very few
of the COVID-19 boxes. Living in the UK, it might be 2025 before I get
tested...).
While the FDA has granted emergency
approval for the use of hydroxychloroquine and chloroquine in COVID-19 patients
(with the EMA limiting use to clinical trials only), definitive evidence for
benefit remains elusive.
A (non-peer reviewed) study from Wuhan
involving patients with mild to moderate COVID-19 symptoms suggests
that hydroxychloroquine treatment may have shortened the time to clinical
recovery[1].
A second study[2] from the French group
which first claimed benefit from treatment with hydroxychloroquine in
combination with the antibiotic azithromycin is proving as
controversial as the first with respect to flaws in design and
interpretation (I recommend Derek Lowe's incisive analysis as a place to
start- "More on Chloroquine/Azithromycin. And On Dr. Raoult.. ", online 23rd March).
New vaccine candidates seem to appear
every other day, with around 50 or so (most at early lab or even concept stage)
now listed. The latest into the clinic, LV-SMENP-DC
(Shenzhen Geno-Immune Medical Institute)[3]
borrows heavily from experimental cancer
vaccines, using antigen-presenting dendritic cells genetically engineered to
express a selection of COVID-19 antigens in combination with antigen-specific
cytotoxic T cells. Primary read out is several years away.
At the other end of the vaccine
innovation spectrum, Australian researchers are about to kick off studies of
the centenarian Bacillus Calmette–Guérin (BCG) tuberculosis vaccine among
healthcare workers[4]. BCG is a powerful
immunostimulant in its own right and the hope is that boosting the innate
immune system, our first line of defence before specific (adaptive) immune
responses develop, might induce some degree of early protection.
The use of convalescent plasma is
gathering pace, with the FDA now coordinating passive immunotherapy studies,
with the Mayo Clinic taking point on clinical studies[5].
A second pilot study out of Wuhan appears to echo earlier encouraging results[6].
[1] Efficacy
of hydroxychloroquine in patients with COVID-19: results of a randomized
clinical trial. Chen Z et al. https://tinyurl.com/s46woam
[2] Clinical
and microbiological effect of a combination of hydroxychloroquine and azithromycin
in 80 COVID-19 patients with at least a six-day follow up: an observational
study. Gautret P et al. https://tinyurl.com/rdsnhoq
[3] Immunity
and Safety of Covid-19 Synthetic Minigene Vaccine. https://tinyurl.com/wmvn8es
[4] BCG
Vaccination to Protect Healthcare Workers Against COVID-19 (BRACE). https://tinyurl.com/qndc9lm
[5] Coronavirus
(COVID-19) Update: FDA Coordinates National Effort to Develop Blood-Related
Therapies for COVID-19. Online April 3rd 2020. https://tinyurl.com/s9x4qqy
[6] The
feasibility of convalescent plasma therapy in severe COVID-19 patients: a pilot
study. Duan, K et al. https://tinyurl.com/sbaqc25
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