Non-specific effects of vaccines: plausible and potentially important, but implications uncertain

Andrew J Pollard, Adam Finn, Nigel Curtis

Research output: Contribution to journalReview article (Academic Journal)peer-review

86 Citations (Scopus)
569 Downloads (Pure)


Non-specific effects (NSE) or heterologous effects of vaccines are proposed to explain observations in some studies that certain vaccines have an impact beyond the direct protection against infection with the specific pathogen for which the vaccines were designed. The importance and implications of such effects remain controversial. There are several known immunological mechanisms which could lead to NSE, since it is widely recognised that the generation of specific immunity is initiated by non-specific innate immune mechanisms that may also have wider effects on adaptive immune function. However, there are no published studies that demonstrate a mechanistic link between such immunological phenomena and clinically relevant NSE in humans. While it is highly plausible that some vaccines do have NSE, their magnitude and duration, and thus importance, remain uncertain. Although the WHO recently concluded that current evidence does not justify changes to immunisation policy, further studies of sufficient size and quality are needed to assess the importance of NSE for all-cause mortality. This could provide insights into vaccine immunobiology with important implications for infant health and survival.

Original languageEnglish
Pages (from-to)1077-1081
Number of pages5
JournalArchives of Disease in Childhood
Issue number11
Early online date13 May 2017
Publication statusPublished - 30 Nov 2017


  • Communicable Diseases
  • Humans
  • Immunity, Heterologous
  • Infant
  • Vaccines
  • Journal Article
  • Review


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