Trending Now - Vitamin D Shows Potential in Alleviating Long COVID Symptoms

WHO:

Dr. JoAnn Manson, senior author of the study, physician at Mass General Brigham

Dr. Marty Makary, Food and Drug Administration Commissioner

Researchers at Mass General Brigham

1,747 adults who tested positive for COVID-19 and 277 household members participating in the study

WHAT:

A study examined the effects of high doses of vitamin D on COVID-19 outcomes, including long COVID symptoms

Participants were assigned to receive either vitamin D3 supplements (9,600 IU/day for two days followed by 3,200 IU/day) or a placebo for four weeks

21% of participants taking vitamin D reported at least one ongoing symptom eight weeks after infection, compared to 25% in the placebo group

The study found no significant change in short-term outcomes such as symptom severity, hospital visits, or emergency care between the vitamin D and placebo groups

WHERE:

The study was conducted at Mass General Brigham, with participants from the United States and Mongolia

WHEN:

The U.S. portion of the trial ran from December 2020 through September 2022

The Mongolia study took place from September 2021 to April 2022

Participants began taking vitamin D or placebo approximately three days after receiving their positive COVID-19 test

WHY:

The study aimed to investigate whether vitamin D supplementation could influence long COVID outcomes and reduce the risk of developing long-term symptoms

HOW:

The study was a randomized clinical trial with stratified randomization and statistical weighting to balance factors affecting COVID-19 outcomes among participants

(UPDATED March 15, 2026 19:07 UTC)

A new study from Mass General Brigham, led by Dr. JoAnn Manson and involving 1,747 adults who tested positive for COVID-19, explored the effects of high doses of vitamin D on long COVID symptoms. Participants received either vitamin D3 supplements or a placebo for four weeks, and while 21% of those taking vitamin D reported ongoing symptoms eight weeks after infection, this was only slightly lower than the 25% in the placebo group, with no significant differences in short-term outcomes. The research, which included participants from both the U.S. and Mongolia, aimed to determine if vitamin D could help reduce the risk of long-term symptoms following COVID-19.