Non-specific effects of vaccination
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《英国医生杂志》
Vaccines have non-specific (heterologous) effects
EDITOR—I support Fine's plea that we review the optimal immunisation schedule in developing countries using evidence from controlled trials rather than observational data.1 There are almost no controlled trials of the effect on mortality from all causes for any of the vaccines in the World Health Organization's schedule.
Fine says, incorrectly, that literature does not support non-specific effects of vaccines.
Firstly, BCG protects against leprosy and is the treatment of choice for some types of bladder cancer.2
Secondly, an individual's history of previous infection or immunisation can clearly influence the response to subsequent infections—immunologists call this heterologous immunity, rather than non-specific immunity.3 4
Thirdly, evidence that vaccines have heterologous effects comes from controlled trials, and not just observational studies.5
It is important to be clear about what is meant by the hypothesis that vaccines have heterologous (non-specific) effects. The hypothesis says that in high mortality areas, vaccines may affect mortality from diseases other than the target disease (for example, measles vaccine may reduce mortality from infectious diseases other than measles); these effects are much stronger in girls than boys; they are strongest in the first three to six months after immunisation; and they are largely determined by the most recent vaccine received.
The immunological basis of heterologous immunity is now well established,3 4 and this knowledge should be used to help design controlled trials to determine the optimal immunisation schedule for children in developing countries. Millions of lives could be saved.
Frank Shann, director of intensive care
Intensive Care Unit, Royal Children's Hospital, Parkville, VIC 3052, Australia frank.shann@rch.org.au
Competing interests: None declared.
References
Fine PEM. Non-specific "non-effects" of vaccination. BMJ 2004;329: 1297-8. (4 December.)
Parfitt K. Martindale: the complete drug reference. 32nd ed. London: Pharmaceutical Press, 1999: 1504-6.
Welsh RM, Selin LK. No one is naive: the significance of heterologous T-cell immunity. Nat Rev Immunol 2002;2: 417-46.
Brehm MA, Selin LK, Welsh RM. CD8 T cell responses to viral infections in sequence. Cellul Microbiol 2004;6: 411-21.
Shann F. Heterologous immunity and the nonspecific effects of vaccines: a major medical advance? Pediatr Infect Dis J 2004;23: 555-8.
EDITOR—I support Fine's plea that we review the optimal immunisation schedule in developing countries using evidence from controlled trials rather than observational data.1 There are almost no controlled trials of the effect on mortality from all causes for any of the vaccines in the World Health Organization's schedule.
Fine says, incorrectly, that literature does not support non-specific effects of vaccines.
Firstly, BCG protects against leprosy and is the treatment of choice for some types of bladder cancer.2
Secondly, an individual's history of previous infection or immunisation can clearly influence the response to subsequent infections—immunologists call this heterologous immunity, rather than non-specific immunity.3 4
Thirdly, evidence that vaccines have heterologous effects comes from controlled trials, and not just observational studies.5
It is important to be clear about what is meant by the hypothesis that vaccines have heterologous (non-specific) effects. The hypothesis says that in high mortality areas, vaccines may affect mortality from diseases other than the target disease (for example, measles vaccine may reduce mortality from infectious diseases other than measles); these effects are much stronger in girls than boys; they are strongest in the first three to six months after immunisation; and they are largely determined by the most recent vaccine received.
The immunological basis of heterologous immunity is now well established,3 4 and this knowledge should be used to help design controlled trials to determine the optimal immunisation schedule for children in developing countries. Millions of lives could be saved.
Frank Shann, director of intensive care
Intensive Care Unit, Royal Children's Hospital, Parkville, VIC 3052, Australia frank.shann@rch.org.au
Competing interests: None declared.
References
Fine PEM. Non-specific "non-effects" of vaccination. BMJ 2004;329: 1297-8. (4 December.)
Parfitt K. Martindale: the complete drug reference. 32nd ed. London: Pharmaceutical Press, 1999: 1504-6.
Welsh RM, Selin LK. No one is naive: the significance of heterologous T-cell immunity. Nat Rev Immunol 2002;2: 417-46.
Brehm MA, Selin LK, Welsh RM. CD8 T cell responses to viral infections in sequence. Cellul Microbiol 2004;6: 411-21.
Shann F. Heterologous immunity and the nonspecific effects of vaccines: a major medical advance? Pediatr Infect Dis J 2004;23: 555-8.