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Randomized trial · measured the question itself

4-week trial in 248 daycare children in Taiwan: no clear difference in flu risk

Huang and colleagues · Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi · 2022

Original title: A randomized trial of vitamin D supplementation to prevent seasonal influenza and enterovirus infection in children.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

No difference

Flu risk was 84% lower with vitamin D but did not reach statistical significance (log-rank test, p = 0.055). Enterovirus infection was similar in both groups (p = 0.946).

The study at a glance

Type of study
Randomized trial
Who or what was studied
248 people · Children aged 2 to 5 in daycare in Taiwan
What was tested
2000 IU of vitamin D a day vs placebo for 1 month, then 6 months of follow-up
What it measured
The question itself: colds, flu and other respiratory infections
Daily amount
2000 IU a day
How long
4 weeks
Who has a stake
No stake declared
No competing interests declared.
Journal
Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi, 2022
Source
PubMed record 35283046. This page is based on the abstract only.

How much this study counts

  • ✓Randomized: people were put into groups by chance, so the groups start out alike.
  • ✓Compared with a placebo, a dummy treatment.
  • •Medium size: 248 people.
  • –Short: 4 weeks. Longer-term effects are unknown.
  • ✓Measured the question itself: colds, flu and other respiratory infections.
  • ✓No competing interests declared.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

  1. Trials in people: colds, flu and chest infections

    10

    2 benefit, 8 no difference

    ↑ This study is the ringed dot

  2. Trials in people: other measures

    5

    1 benefit, 1 mixed, 2 no difference, 1 harm

  3. Trials in people: lab tests or safety

    1

    1 no difference

  4. Population studies

    1

    1 no difference

  5. Blood levels and genes

    4

    3 benefit, 1 no difference

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does vitamin D prevent colds and infections?”

Not clearly; any effect looks small.

Confidence: low. Based on 33 on-topic papers.

Read the full answer

Of the other 9 papers on the same step: 2 benefit, 7 no difference. This one found no difference. It agrees with most of them.

Other papers on the same step

See all 33 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The reviewer corrected 1 field after reading the abstract. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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