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Chickenpox

Rising Chickenpox Cases in Australia: Understanding the Virus, Vaccination, and Prevention

Strategic Insights

— 2 min read

With 2,010 notified cases so far this year, chickenpox has been spreading across Australia, with alerts issued in Northern New South Wales. The highly contagious varicella zoster virus typically causes a mild illness in children but can be severe in adults, and those with abnormal immune systems. Symptoms begin with fever, runny nose, fatigue, and cough, followed by a distinctive fluid-filled blistering rash. The virus usually causes a mild illness in children but can be severe in adults, and in those with abnormal immune systems such as transplant patients. It can also affect the unborn fetus if pregnant women are infected, causing a condition called congenital varicella syndrome, with lifelong disability.

Key Takeaways:

  • Chickenpox is a highly contagious infection caused by the varicella zoster virus, which spreads through respiratory secretions and skin lesions, affecting up to 90% of people who aren't immune and are in close contact with an infected person.
  • The virus typically causes a mild illness in children but can be severe in adults and those with abnormal immune systems, such as transplant patients, potentially causing life-long disability.
  • The varicella vaccine is a live vaccine funded by the National Immunisation Program at 18 months, with a single dose preventing disease in approximately 65% of cases and protecting against severe disease in up to 82% of cases.
  • The vaccine is administered in combination with the measles, mumps, and rubella vaccine, with two doses providing overall protection of about 95%, but a second dose is not currently funded, and individuals aged 14 years and over who aren't immune require two doses for optimal protection.
  • The vaccine has led to a decline in hospitalisations due to chickenpox, with a 74% reduction in hospitalisations from 2000-2003 and 2011-2014, and no reported deaths in children under 15 since 2008.
  • Infections in children too young to be vaccinated have fallen by 67%, reflecting herd immunity, which protects vulnerable members of the community from severe disease.
  • Australia also has a shingles vaccine (Shingrix), a non-live vaccine for adults, which boosts the immune system to stop the varicella virus from escaping nerve cells and causing shingles, although it doesn't prevent chickenpox.
  • People can check if they or their child have had the chickenpox vaccine by examining their immunisation record, and contacting their GP if it's not listed or available.

Statistics:

  • 2,010 notified chickenpox cases in Australia so far this year.
  • The varicella vaccine prevents disease in approximately 65% of cases and protects against severe disease in up to 82% of cases with a single dose.
  • Two doses of the varicella vaccine provide overall protection of about 95%.
  • A 74% reduction in hospitalisations from chickenpox from 2000-2003 to 2011-2014.
  • No reported deaths in children under 15 due to chickenpox since 2008.
  • 67% decline in infections in children too young to be vaccinated.

Sources:

  • The Conversation -- Can you get chickenpox twice? Or if you're vaccinated? Experts answer 9 key questions -- https://theconversation.com/can-you-get-chickenpox-twice-or-if-youre-vaccinated-experts-answer-9-key-questions-267741
  • SBDIGIT/Getty Images (linked in the original article)
  • Archana Koirala -- Paediatrician and Infectious Diseases Specialist; Clinical Researcher, University of Sydney

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