Doxycycline plus zinc helps shield against COVID-19

In healthcare workers, prophylactic therapy with doxycycline plus zinc seems to reduce the risk of contracting SARS-CoV-2 infection, according to a study.

The study examined the effect of the combined treatment with doxycycline plus zinc in the primary prevention of COVID-19 infection in 172 Tunisian healthcare workers (mean age 38.4 years). They were randomized to receive one of the following: a combination preventive treatment dose of doxycycline (100 mg/day) plus zinc (15 mg/day; n=59), a single-dose treatment with doxycycline (n=56), or a placebo (n=57).

Researchers evaluated the effectiveness of preventive treatment by the extent of decline in the number of cases of COVID-19 infection and/or a decrease in the viral load determined by SARS-CoV-2 cycle threshold (Ct) value using RT-PCR test.

The levels of exposure to COVID-19 infection in the workplace varied among the participants, with 40 (23.3 percent) involved with invasive bedside procedures with COVID-19 positive patients, 19 (11.0 percent) with intraoperative procedure, and 113 (65.7 percent) with routine care.

Compared with the doxycycline alone and the placebo groups, the combination group had a significantly lower incidence of SARS-CoV-2 infection. At day 49, a total of 24 participants tested positive for SARS-CoV-2 (14.0 percent), including five (8.5 percent) in the combination group, five (8.9 percent) in the doxycycline group, and 14 (24.6 percent) in the placebo group (p=0.018).

COVID-19 infection incidence was not associated with diabetes (p=0.51), nor with hypertension (p=0.99), asthma (p=0.52), and chronic obstructive pulmonary disease (p=0.27).

The findings suggest that the combination of doxycycline and zinc may exert a protective effect against SARS-CoV-2 infection.