What is the WHO‑recommended vitamin A dosing regimen for a child with measles, including doses for different age groups?

Vitamin A Dosing for Measles in Children

The WHO-recommended vitamin A dosing regimen for measles is 200,000 IU orally for children ≥12 months and 100,000 IU orally for children <12 months, given on day 1, with a second identical dose on day 2 for complicated measles. 1, 2

Standard Dosing Protocol

Age-Based Dosing

• Children ≥12 months (including adults): 200,000 IU oral vitamin A on day 1 1, 2, 3
• Children <12 months (including infants under 6 months): 100,000 IU oral vitamin A on day 1 1, 4, 2
• Important caveat: Do not administer if the child has received vitamin A supplementation in the preceding month 2

Two-Dose Regimen for Complicated Measles

Administer a second identical dose on day 2 when any of the following complications are present: 1, 2, 3

• Pneumonia or acute lower respiratory infection
• Otitis media
• Croup or laryngotracheobronchitis
• Diarrhea with moderate or severe dehydration
• Neurological problems (including encephalitis)

The evidence for this two-dose regimen is compelling: it produces a 64% reduction in overall mortality (RR 0.36), a 67% reduction in pneumonia-specific mortality (RR 0.33), and an 82% mortality reduction in children under 2 years of age (RR 0.18). 2, 3, 5 In contrast, a single dose of 200,000 IU showed no significant mortality benefit (RR 0.77). 3

Extended Protocol for Vitamin A Deficiency with Eye Signs

If any eye symptoms of vitamin A deficiency are present, administer a third dose 1-4 weeks after the initial two doses. 1, 2 Eye signs requiring this extended protocol include: 1

• Xerosis (dryness of conjunctiva or cornea)
• Bitot's spots (foamy conjunctival patches)
• Keratomalacia (corneal softening)
• Corneal ulceration

The dosing schedule for eye manifestations is: 1

• Day 1: 200,000 IU (or 100,000 IU if <12 months)
• Day 2: 200,000 IU (or 100,000 IU if <12 months)
• 1-4 weeks later: 200,000 IU (or 100,000 IU if <12 months)

Critical Clinical Context

Why Two Doses Matter

The superiority of the two-dose regimen over a single dose is well-established in high-mortality settings. 3, 5 Water-based formulations showed an 81% mortality reduction (RR 0.19) compared to 48% for oil-based preparations (RR 0.52), though both formulations are effective. 3 The benefit is most pronounced in children under 2 years and in hospitalized children in areas with high case fatality rates. 3, 5, 6

Common Pitfalls to Avoid

• Do not delay vitamin A administration waiting for laboratory confirmation—treatment should begin based on clinical diagnosis. 4
• Do not withhold vitamin A due to toxicity concerns—the standard protocol is safe, as acute toxicity requires >300,000 IU in adults or >60,000 IU in children within hours/days. 1
• Do not forget the second dose on day 2 for complicated measles—this is where the mortality benefit is demonstrated. 2, 3
• Do not administer to children who received vitamin A in the past month—this prevents excessive dosing. 2

Special Population: Infants Under 6 Months

Infants under 6 months face particularly high mortality and complication risks because they are too young for routine measles vaccination and maternal antibodies may have waned. 4 These infants receive the same two-dose protocol as older infants: 100,000 IU on day 1 and 100,000 IU on day 2 for complicated measles. 4

Routine Follow-Up Supplementation

In populations at risk for vitamin A deficiency, continue vitamin A supplementation every 3 months after completing the acute measles treatment protocol. 7, 1