The long-term duration of protection from varicella vaccine is unknown, but there are now persons vaccinated twenty years ago with no evidence of waning immunity, while others have become vulnerable in as few as six years. Assessments of duration of immunity are complicated in an environment where natural disease is still common, which typically leads to an overestimation of effectiveness.
Catching "wild" chickenpox as a child has been thought to commonly result in lifelong immunity. Indeed, parents have deliberately ensured this in the past with "pox parties". Historically, exposure of adults to contagious children has boosted their immunity, reducing the risk of shingles. The CDC and corresponding national organisations are carefully observing the failure rate which may be high compared with other modern vaccines-large outbreaks of chickenpox having occurred at schools which required their children to be vaccinated.
Kategori produk : Vaksin Varicella (Live) > Produk akhir