Pediatrics

Varicella Vaccine and Pediatric Stroke: A Q&A With Dr Shannon MacDonald

While varicella is a well-known risk factor for pediatric arterial ischemic stroke (AIS), it is unknown whether the varicella vaccine also poses a risk for children. A new study, “Is varicella vaccination associated with pediatric arterial ischemic stroke? A population-based cohort study,” which is being published in the May issue of Vaccine, examined this association closer.

Consultant360 spoke with the lead author of the study, Shannon MacDonald, PhD, RN, who is an assistant professor of nursing at the University of Alberta, adjunct assistant professor in the School of Public Health at the University of Alberta, and adjunct assistant professor in the Department of Pediatrics at the Cumming School of Medicine at University of Calgary.

 

Shannon MacDonald nursing

 

Consultant360: Varicella disease is a known risk factor for arterial ischemic stroke in children. What is the mechanism between the two?

Shannon MacDonald: Infectious processes such as varicella (chickenpox) disease are known risk factors for AIS.1 Although the mechanism of action has not been definitively determined, there is evidence to suggest that the varicella infection can spread to large cerebral arteries, leading to vessel-wall inflammation, secondary thrombosis, and ultimately AIS in rare incidences.2

 

C360: Did your study find a connection between the varicella vaccine and arterial ischemic stroke in children? And what was the reason for this?

SM: No, we found no relationship between varicella vaccination and AIS in children, meaning that AIS was not more common in children who received varicella vaccine as compared with children who were not vaccinated. This confirms findings of a large study in the United States that looked at the link between varicella and AIS,3 as well as a large, international study of childhood AIS risk factors that found evidence of a protective effect against AIS from completing recommended childhood vaccinations.4 It is reassuring that multiple studies using different data sources and in different settings came to the same conclusions, as it strengthens the evidence that varicella vaccine does not increase the risk of AIS.  

NEXT: How would you advise parents who are hesitant of vaccinating their children?

 

C360: Pediatric vaccination is a much-debated topic in the United States. How would you advise parents or guardians who are hesitant of vaccinating their children?

SM: Our study does not address this question but does contribute to the body of knowledge related to vaccine safety, which is often a topic of concern to parents. There is strong evidence that routine vaccination of children is protective against a number of severe diseases and the vast majority of parents still diligently follow the recommended vaccination schedule. There is valuable work underway in the United States and Canada, including work by members of our team,5 to explore better ways to communicate and support parents in this decision-making process. Key resources for clinicians and parents are available through the Centers for Disease Control and Prevention,6 the Vaccine Education Centre at the Children’s Hospital of Philadelphia,7 and Immunize Canada.8

 

C360: In your opinion, which pediatric vaccinations should be required for all children? Why?

SM: Though our study does not address this question, we recommend that all children be vaccinated according to current childhood vaccination schedules, such as those recommended by the Advisory Committee on Immunization Practices (ACIP)9 in the United States and the National Advisory Committee on Immunization (NACI)10 in Canada. Although it may seem that children in North America are not at risk for these diseases anymore, most of these diseases are only a plane ride away, as evidenced by recent outbreaks of measles11 and diphtheria12 around the world.

 

 

—Amanda Balbi, Managing Editor, Consultant360

References:

  1. Miravet E, Danchaivijitr N, Basu H, Saunders DE, Ganesan V. Clinical and radiological features of childhood cerebral infarction following varicella zoster virus infection. Dev Med Child Neurol. 2007;49(6):417-422.
  2. Kleinschmidt-DeMasters BK, Gilden DH. Varicella-Zoster virus infections of the nervous system: clinical and pathologic correlates. Arch Pathol Lab Med. 2001;125(6):770-780.
  3. Donahue JG, Kieke BA, Yih WK, et al; Vaccine Safety DataLink Team. Varicella vaccination and ischemic stroke in children: Is there an association? Pediatrics. 2009;123(2):e228-e234.
  4. Fullerton HJ, Hills NK, Elkind MS, et al; VIPS Investigators. Infection, vaccination, and childhood arterial ischemic stroke: Results of the VIPS study. Neurology. 2015;85(17):1459-1466.
  5. Canadian Immunization Research Network. http://cirnetwork.ca. Accessed April 26, 2018.
  6. Centers for Disease Control and Prevention. Vaccines & immunizations. https://www.cdc.gov/vaccines/index.html. Updated April 23, 2018. Accessed April 26, 2018.
  7. Children’s Hospital of Philadelphia. Vaccine education center. http://www.chop.edu/centers-programs/vaccine-education-center. Accessed April 26, 2018.
  8. Immunize Canada. https://immunize.ca. Accessed April 26, 2018.
  9. Centers for Disease Control and Prevention. Recommended immunization schedule for children and adolescents aged 18 years of younger, United States, 2018. https://www.cdc.gov/vaccines/schedules/hcp/child-adolescent.html. Updated March 2, 2018. Accessed April 26, 2018.
  10. Government of Canada. National Advisory Committee on Immunization. https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci.html. Updated March 6, 2018. Accessed April 26, 2018.
  11. World Health Organization. Measles and rubella surveillance data. http://www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/active/measles_monthlydata/en/. Updated April 16, 2018. Accessed April 26, 2018.
  12. Pan American Health Organization and World Health Organization. 16 April 2018: Diphtheria – Epidemiological update. http://www.paho.org/hq/index.php?option=com_content&view=article&id=14256%3A16-april-2018-diphtheria-epidemiological-update&catid=2103%3Arecent-epidemiological-alerts-updates&Itemid=42346&lang=en. Updated April 16, 2018. Accessed April 26, 2018.