Vaccinating to protect a vulnerable subpopulation

Jonathan Dushoff, Joshua B Plotkin, Cecile Viboud, Lone Simonsen, Mark Miller, Mark Loeb, David J. Earn

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

BACKGROUND:
Epidemic influenza causes serious mortality and morbidity in temperate countries each winter. Research suggests that schoolchildren are critical in the spread of influenza virus, while the elderly and the very young are most vulnerable to the disease. Under these conditions, it is unclear how best to focus prevention efforts in order to protect the population. Here we investigate the question of how to protect a population against a disease when one group is particularly effective at spreading disease and another group is more vulnerable to the effects of the disease.

METHODS AND FINDINGS:
We developed a simple mathematical model of an epidemic that includes assortative mixing between groups of hosts. We evaluate the impact of different vaccine allocation strategies across a wide range of parameter values. With this model we demonstrate that the optimal vaccination strategy is extremely sensitive to the assortativity of population mixing, as well as to the reproductive number of the disease in each group. Small differences in parameter values can change the best vaccination strategy from one focused on the most vulnerable individuals to one focused on the most transmissive individuals.

CONCLUSIONS:
Given the limited amount of information about relevant parameters, we suggest that changes in vaccination strategy, while potentially promising, should be approached with caution. In particular, we find that, while switching vaccine to more active groups may protect vulnerable groups in many cases, switching too much vaccine, or switching vaccine under slightly different conditions, may lead to large increases in disease in the vulnerable group. This outcome is more likely when vaccine limitation is stringent, when mixing is highly structured, or when transmission levels are high.
OriginalsprogEngelsk
TidsskriftPLOS Medicine
Vol/bind4
Udgave nummer5
Sider (fra-til)921-927
ISSN1549-1277
StatusUdgivet - 2007

Citer dette

Dushoff, J., Plotkin, J. B., Viboud, C., Simonsen, L., Miller, M., Loeb, M., & Earn, D. J. (2007). Vaccinating to protect a vulnerable subpopulation. PLOS Medicine, 4(5), 921-927.
Dushoff, Jonathan ; Plotkin, Joshua B ; Viboud, Cecile ; Simonsen, Lone ; Miller, Mark ; Loeb, Mark ; Earn, David J. / Vaccinating to protect a vulnerable subpopulation. I: PLOS Medicine. 2007 ; Bind 4, Nr. 5. s. 921-927.
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title = "Vaccinating to protect a vulnerable subpopulation",
abstract = "BACKGROUND:Epidemic influenza causes serious mortality and morbidity in temperate countries each winter. Research suggests that schoolchildren are critical in the spread of influenza virus, while the elderly and the very young are most vulnerable to the disease. Under these conditions, it is unclear how best to focus prevention efforts in order to protect the population. Here we investigate the question of how to protect a population against a disease when one group is particularly effective at spreading disease and another group is more vulnerable to the effects of the disease.METHODS AND FINDINGS:We developed a simple mathematical model of an epidemic that includes assortative mixing between groups of hosts. We evaluate the impact of different vaccine allocation strategies across a wide range of parameter values. With this model we demonstrate that the optimal vaccination strategy is extremely sensitive to the assortativity of population mixing, as well as to the reproductive number of the disease in each group. Small differences in parameter values can change the best vaccination strategy from one focused on the most vulnerable individuals to one focused on the most transmissive individuals.CONCLUSIONS:Given the limited amount of information about relevant parameters, we suggest that changes in vaccination strategy, while potentially promising, should be approached with caution. In particular, we find that, while switching vaccine to more active groups may protect vulnerable groups in many cases, switching too much vaccine, or switching vaccine under slightly different conditions, may lead to large increases in disease in the vulnerable group. This outcome is more likely when vaccine limitation is stringent, when mixing is highly structured, or when transmission levels are high.",
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Dushoff, J, Plotkin, JB, Viboud, C, Simonsen, L, Miller, M, Loeb, M & Earn, DJ 2007, 'Vaccinating to protect a vulnerable subpopulation', PLOS Medicine, bind 4, nr. 5, s. 921-927.

Vaccinating to protect a vulnerable subpopulation. / Dushoff, Jonathan; Plotkin, Joshua B; Viboud, Cecile; Simonsen, Lone; Miller, Mark; Loeb, Mark; Earn, David J.

I: PLOS Medicine, Bind 4, Nr. 5, 2007, s. 921-927.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Vaccinating to protect a vulnerable subpopulation

AU - Dushoff, Jonathan

AU - Plotkin, Joshua B

AU - Viboud, Cecile

AU - Simonsen, Lone

AU - Miller, Mark

AU - Loeb, Mark

AU - Earn, David J.

PY - 2007

Y1 - 2007

N2 - BACKGROUND:Epidemic influenza causes serious mortality and morbidity in temperate countries each winter. Research suggests that schoolchildren are critical in the spread of influenza virus, while the elderly and the very young are most vulnerable to the disease. Under these conditions, it is unclear how best to focus prevention efforts in order to protect the population. Here we investigate the question of how to protect a population against a disease when one group is particularly effective at spreading disease and another group is more vulnerable to the effects of the disease.METHODS AND FINDINGS:We developed a simple mathematical model of an epidemic that includes assortative mixing between groups of hosts. We evaluate the impact of different vaccine allocation strategies across a wide range of parameter values. With this model we demonstrate that the optimal vaccination strategy is extremely sensitive to the assortativity of population mixing, as well as to the reproductive number of the disease in each group. Small differences in parameter values can change the best vaccination strategy from one focused on the most vulnerable individuals to one focused on the most transmissive individuals.CONCLUSIONS:Given the limited amount of information about relevant parameters, we suggest that changes in vaccination strategy, while potentially promising, should be approached with caution. In particular, we find that, while switching vaccine to more active groups may protect vulnerable groups in many cases, switching too much vaccine, or switching vaccine under slightly different conditions, may lead to large increases in disease in the vulnerable group. This outcome is more likely when vaccine limitation is stringent, when mixing is highly structured, or when transmission levels are high.

AB - BACKGROUND:Epidemic influenza causes serious mortality and morbidity in temperate countries each winter. Research suggests that schoolchildren are critical in the spread of influenza virus, while the elderly and the very young are most vulnerable to the disease. Under these conditions, it is unclear how best to focus prevention efforts in order to protect the population. Here we investigate the question of how to protect a population against a disease when one group is particularly effective at spreading disease and another group is more vulnerable to the effects of the disease.METHODS AND FINDINGS:We developed a simple mathematical model of an epidemic that includes assortative mixing between groups of hosts. We evaluate the impact of different vaccine allocation strategies across a wide range of parameter values. With this model we demonstrate that the optimal vaccination strategy is extremely sensitive to the assortativity of population mixing, as well as to the reproductive number of the disease in each group. Small differences in parameter values can change the best vaccination strategy from one focused on the most vulnerable individuals to one focused on the most transmissive individuals.CONCLUSIONS:Given the limited amount of information about relevant parameters, we suggest that changes in vaccination strategy, while potentially promising, should be approached with caution. In particular, we find that, while switching vaccine to more active groups may protect vulnerable groups in many cases, switching too much vaccine, or switching vaccine under slightly different conditions, may lead to large increases in disease in the vulnerable group. This outcome is more likely when vaccine limitation is stringent, when mixing is highly structured, or when transmission levels are high.

M3 - Journal article

VL - 4

SP - 921

EP - 927

JO - PLOS Medicine

JF - PLOS Medicine

SN - 1549-1277

IS - 5

ER -

Dushoff J, Plotkin JB, Viboud C, Simonsen L, Miller M, Loeb M et al. Vaccinating to protect a vulnerable subpopulation. PLOS Medicine. 2007;4(5):921-927.