Varicella Vaccine and Aspirin Interaction
Yes, there is a clinically significant interaction between varicella vaccine and aspirin—vaccine recipients should avoid salicylates (aspirin) for 6 weeks after vaccination due to the theoretical risk of Reye syndrome. 1, 2
The Core Recommendation
The Advisory Committee on Immunization Practices (ACIP) and FDA recommend that vaccine recipients avoid using salicylates for 6 weeks after receiving varicella vaccines because of the association between aspirin use and Reye syndrome after varicella infection. 1, 2
Importantly, no adverse events associated with the use of salicylates after varicella vaccination have actually been reported—this recommendation is based on theoretical risk extrapolated from the well-established association between aspirin and Reye syndrome in natural varicella infection. 1
Special Consideration for Children on Therapeutic Aspirin
Vaccination with subsequent close monitoring should be considered for children who have rheumatoid arthritis or other conditions requiring therapeutic aspirin. 1
The rationale: The risk for serious complications associated with aspirin is likely to be greater in children in whom natural varicella develops than it is in children who receive the vaccine containing attenuated VZV. 1
This means that for children on chronic aspirin therapy (such as those with Kawasaki disease or juvenile rheumatoid arthritis), the benefit of vaccination may outweigh the theoretical risk, but requires careful clinical monitoring. 1
Understanding Reye Syndrome Risk
Reye syndrome is characterized by encephalopathy and fatty degeneration of the liver, usually occurring after influenza or varicella, with a strong epidemiologic link to salicylate use. 3, 4
The case fatality rate for Reye syndrome is approximately 31%, making this a serious concern despite its rarity. 4
After warnings about aspirin use in children with viral infections were issued in 1980, reported cases of Reye syndrome declined sharply from 555 cases in 1980 to no more than 36 cases per year since 1987. 4
Safe Alternatives
No association has been documented between Reye syndrome and analgesics or antipyretics that do not contain salicylic acid (such as acetaminophen or ibuprofen). 1
These non-salicylate medications can be used safely for fever or pain management after varicella vaccination. 1
Critical Clinical Pitfalls to Avoid
Do not assume all pain relievers are contraindicated—only salicylate-containing products need to be avoided; acetaminophen and ibuprofen are safe alternatives. 1
Do not withhold vaccination from children on chronic aspirin therapy without considering the risk-benefit ratio—natural varicella infection poses greater risk than the attenuated vaccine virus. 1
Remember the 6-week timeframe—this is the period during which salicylates should be avoided, not indefinitely. 1, 2
This precaution applies to children and adolescents 12 months through 17 years of age specifically, as Reye syndrome predominantly affects this age group. 2