Hydroxychloroquine for prophylaxis and treatment of COVID-19 in health care workers
et al., New Microbes and New Infections,
100% reduction in cases with HCQ+zinc post-exposure prophylaxis. Brief report for healthcare workers in Bulgaria.
0 cases with treatment vs. 3 for control.
156 treatment patients and 48 control patients.
No serious adverse events. This paper reports on both PEP and early treatment, we have separated the two studies.
risk of case, 92.7% lower, RR 0.07, p = 0.01, treatment 0 of 156 (0.0%), control 3 of 48 (6.2%), NNT 16, relative risk is not 0 because of continuity correction due to zero events (with reciprocal of the contrasting arm).
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Simova et al., 12 Nov 2020, retrospective, Bulgaria, peer-reviewed, 5 authors.
Abstract: LETTER TO THE EDITOR
prophylaxis and treatment of
COVID-19 in health-care workers
I. Simova1,2, T. Vekov2, J. Krasnaliev1,2, V. Kornovski2,3 and
1) Heart and Brain—University Hospital, Pleven, 2) Bulgarian Cardiac
Institute, Soﬁa and 3) Heart and Brain—University Hospital, Burgas,
Keywords: COVID-19, health-care workers,
hydroxychloroquine, prophylaxis, treatment
Original Submission: 19 October 2020; Revised Submission:
28 October 2020; Accepted: 6 November 2020
Article published online: 12 November 2020
Corresponding author: I. Simova, Heart and Brain—University
Hospital, Pleven, Bulgaria.
To the Editor,
Providing adequate health care is vitally important during the
coronavirus disease 2019 (COVID-19) pandemic to keep
morbidity and mortality low. Health-care workers (HCW) are key
guarantees for this process, and they must feel safe and adequately
protected, which includes reliable prophylactic measures .
Hydroxychloroquine (HCQ) could exert antiviral effects,
essential for prophylaxis and early treatment of COVID-19,
through several mechanisms: (a) endosomal pH increase,
which inhibits the passage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through the host cells’
membranes; (b) inhibition of angiotensin-converting enzyme
2 cell receptor glycosylation, which impedes SARS-CoV-2–receptor binding; (c) blocking the transport of SARS-CoV-2 from
early endosomes to endolysosomes, which prevents release of
the viral genome; (d) immunomodulation; and (e) limiting the
post-viral cytokine storm syndrome [2,3].
We share here the experience of the Bulgarian Cardiac
Institute (BCI) regarding the use of HCQ for prophylaxis and
treatment of COVID-19 in HCW.
The BCI comprises seven hospitals and eight medical centres, with around 1200 HCW, covering more than two-thirds
of Bulgarian territory. Since March 2020, many of our employees have been in close contact with individuals with
COVID-19. We offered prophylaxis with HCQ 200 mg daily
for 14 days to 204 of them. In all, 76.4% of the group (156
HCW) used HCQ and none of them presented with COVID19 symptoms. Of the 48 HCW that refused HCQ prophylaxis, three developed symptoms and tested positive for
During the last 7 months, 38 HCW at BCI have tested
positive for COVID-19, half of them were symptomatic. We
suggest the following treatment regimen as an early homebased therapy for them: azithromycin 500 mg daily; HCQ
200 mg three times a day and zinc up to 50 mg daily for 14 days.
Thirty-three (86.8%) of them undertook this treatment, their
symptoms disappeared between days 2 and 4, none of them
required hospitalization and all had a negative PCR test on day
14. The other ﬁve HCW (13.2%) used alternative treatment
regimens, none of them including HCQ. Three of them still
tested positive at day 14 and two of them required
All HCW (189) treated with HCQ, also took zinc. We
performed electrocardiograms at baseline, and on day 3 and day
5 of HCQ treatment using a QTc measurement: baseline QTc
was 412 ± 23 ms, day 3 QTc was 429 ± 27 ms and day 5 QTc
was 427 ± 31 ms (p > 0.05 for all comparisons). We registered
a QTc increase 60 ms in ﬁve HCW. QTc increased >470 ms
in one male HCW and >480 ms in three female HCW. On all of
these occasions HCQ was stopped. We did not register any
A possible drawback of HCQ prophylaxis is the risk for
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