This was looked at in a randomised study published 12th February 2021 in the Journal of the American Medical Association’s Network Open.
The randomised clinical trial by Thomas and others examined whether high dose zinc and/or high dose vitamin C reduced the severity or duration of symptoms compared with usual care amongst ambulatory patients with COVID-19 infection.
Unfortunately, limited evidence exist regarding whether the early treatment of novel SARS-CoV-2 infection mitigates symptom progression.
Zinc and vitamin C are commonly available over the counter supplements whilst patients often take for the treatment of viral illnesses.
It is suggested that zinc increases the white cells’ ability to fight infection and vitamin C is an antioxidant that may play a role in immune response.
There is limited evidence to suggest that high doses of vitamin C and zinc may reduce the duration of common cold symptoms and decrease the severity of symptoms.
However, the role of zinc and vitamin C in decreasing symptoms and improving recovery in patients diagnosed with COVID-19 infection is uncertain.
This study sought to determine whether zinc and vitamin C reduced the severity of symptoms compared with usual care.
The study was a multicentre single health system randomised clinical factorial open label trial which enrolled 214 adult patients confirmed by PCR swab. The patients were randomised to receive either zinc or vitamin C or both or just standard care.
The primary endpoint was the number of days required to reach a 50% reduction in symptoms including severity of fever, cough, shortness of breath and fatigue. The secondary endpoint included days required to reach a total symptom severity score of zero cumulative severity score at day five, hospitalisations, deaths, adjunctive prescribed medications and adverse effects of the study supplements.
A total of 214 patients were randomised with a mean age of 45.2 years and 132 were women, which is 61.7%. The study was stopped for a low conditional power for benefit with no significant difference amongst the four groups for the primary endpoint.
Patients who received usual care without supplementation achieved a 50% reduction in symptoms at about 6.7 days compared with 5.5 days for the vitamin C group, 5.9 days for the zinc group and 5.5 days for the group receiving both. There was unfortunately no significant difference in secondary outcomes amongst the treatment group.
The study therefore concluded that treatment with high dose zinc, vitamin C or a combination of the two did not significantly decrease the duration of symptoms compared with standard care.
Dr Paul Ettlinger
BM, DRCOG, FRCGP, FRIPH, DOccMed