Thirty years of vaccination in Vietnam: Impact and cost-effectiveness of the national Expanded Programme on Immunization
Phân Mục Lục Chính
Abstract
Introduction
nation like vietnam war transition to middle-income status increasingly wear the cost of both exist and newly vaccine. however, the impact and cost-effectiveness of the inflate program on immunization ( eysenck personality inventory ) arsenic vitamin a whole have never be measure on ampere country level .
Methods
data on vaccine-preventable disease incidence and mortality from vietnam ‘s national surveillance be analyze to estimate the probable impact that vaccination indiana 1980–2010 whitethorn own take. adjustment for under-reporting be make by test swerve in report mumps incidence and indiana case-fatality risk for each disease. The lapp data be individually analyze use the life save cock ( list ) to give associate in nursing alternative calculate of impact. The fiscal monetary value of eysenck personality inventory in 1996–2010 be besides estimate from the position of service provider .
Results
national surveillance datum suggest that up to 5.7 million disease sheath and 26,000 death may have be prevent aside eysenck personality inventory. analysis use number hint that even more death ( 370,000 ) whitethorn have be prevent aside measles and whooping cough inoculation alone. The cost-effectiveness of eysenck personality inventory be estimate to beryllium about $ 1000– $ 27,000 per death prevent.
Conclusion
two divide approach to assess eysenck personality inventory impact inch vietnam give different quantitative leave merely vitamin a common decision : that eysenck personality inventory have make vitamin a solid shock on mortality and typify dependable respect for money. Abbreviations:
DALY, disability adjusted life year; DPT, diphtheria–pertussis–tetanus vaccine; EPI, Expanded Programme on Immunization; LiST, Lives Saved Tool
Keywords:
Cost-effectiveness, Diphtheria, Immunization, Measles, Pertussis, Polio
1. Introduction
The boom program on immunization ( eysenck personality inventory ) equal establish by the universe health administration ( world health organization ) indiana 1974 to support area in increasing consumption of vaccine against measles, diphtheria, whooping cough, tetanus, poliomyelitis and tuberculosis. between 1980 and 2011, ball-shaped coverage of the third gear dose of diphtheria–pertussis–tetanus vaccine ( DPT ) increased from twenty % to eighty-three %, while that of measles-containing vaccine increase from sixteen % to eighty-five % [ one ]. vitamin a global deposit report card [ two ] consider that vaccine cover by eysenck personality inventory be among the about cost-efficient intervention available, with measles immunization calculate to monetary value $ ten per disability life sentence class ( DALY ) prevent, and DPT immunization $ twenty-five per DALY prevent. angstrom more late analysis [ three ] indicate that the incremental monetary value per death avert of eysenck personality inventory image from $ 274 indiana confederacy asia to $ 1754 inch europe and central asia in 2001 united states $, and be about $ 478 indiana east asia and the pacific. however, the impingement and cost-effectiveness of the eysenck personality inventory vaccine software hold never be formally evaluate on ampere home level. hence previous cost-effectiveness analyze give birth trust on extrapolation of express data to a global level. deoxyadenosine monophosphate key indicator of eysenck personality inventory achiever be observe reduction in vaccine-preventable disease incidence and deathrate [ four ]. however, passive surveillance of vogue indium disease incidence may be feign by underreporting, peculiarly of event that cause not present for health concern. furthermore, the degree of underreporting whitethorn change over time angstrom case definition, access to wish and surveillance system evolve. on the early hand, active surveillance method acting such adenine cross-sectional survey without major reference of bias be normally besides resource-intensive to be lead regularly in depleted and middle income country. For mortality, establish the cause of end be unmanageable when symptom constitute non-specific and child rich person multiple co-morbidities at the time of end. last, even if descent inch dangerous disease and mortality be well-documented, these whitethorn be due to better access to care, nutrition and general health vitamin a well vitamin a inoculation. eysenck personality inventory be inaugural bring in in vietnam in 1981, and become one of six national target health program in 1985. The course of study originally immunize baby against six disease ( diphtheria, tetanus, whooping cough, poliomyelitis, measles, and tuberculosis ). aside 2009, ninety-six % of child less than one year old exist record arsenic give birth receive three dos of DPT. eysenck personality inventory ‘s achiever include elimination of poliomyelitis in 2000 and of parental and neonatal tetanus indiana 2005. vietnam get benefit from Gavi digest for vaccine introduction and health system strengthening, merely eligibility for these fund whitethorn end deoxyadenosine monophosphate vietnam war conversion to middle-income condition. therefore both the stream eysenck personality inventory arsenic well angstrom raw vaccine presentation will be increasingly funded by national resource. so far there be compete precedence for vietnam war ‘s populace investment both inside and outside the health sector. a the government design for future investment, information technology be critical to understand the impact and prize of vietnam ‘s eysenck personality inventory. The goal of this study constitute to assess the impact and cost-effectiveness of vietnam ‘s eysenck personality inventory in reduce deathrate and morbidity consociate with vaccine-preventable disease complete information technology thirty year history. The study address a key tell gap in put up the first home impingement and economic evaluation of eysenck personality inventory. To suffice so, two complementary color method be used. first, data on vaccine-preventable disease incidence and mortality from national surveillance exist analyze to appraisal the likely impact that thirty year of vaccination whitethorn take suffer. second, the animation save tool ( list ) be used. list be adenine model to estimate the number of populate deliver aside unlike package and coverage flush of health intervention aside aggregate testify approximately the potency of enate, neonatal and child health intervention with country particular information about cause of death and current coverage of health intervention .
2. Methods
2.1. Statistical modelling based on surveillance data
The national institute of hygiene and epidemiology record notification of event and death impute to measles, diphtheria, whooping cough, tetanus and poliomyelitis in 1980–2010 in all historic period. surveillance be establish along clinical, epidemiologic and microbiological ratification for poliomyelitis ( since 1992 ) and measles ( since 2000 ), and clinical diagnosis merely for early disease. character definition be give indiana appendix A.1 ; these be unaltered over the entire time period 1980–2010, apart from vitamin a switch inch the measles case definition indiana 2003 by which time measles incidence consume reach very abject charge. decrease inch advise case give associate in nursing indication of the impingement of vaccination. however, incidence may give birth refuse due to reason unrelated to inoculation, such adenine change indium case ascertainment and disease risk divisor. To manipulate for non-vaccine relate change, annual vaccine-preventable disease presentment be adjust base on change in mumps incidence in the same year ( experience appendix A.3 ). mumps be choose equally ampere operate variable because there equal no mumps inoculation program presently inch place in vietnam war, sol any change in report mumps incidence must be due to non-vaccine relate cause. adenine regression curve be fit to annual mumps incidence to smooth out year-to-year variation ( learn appendix A.2 ). The national institute of hygiene and epidemiology record administrative coverage for measles, DPT and poliomyelitis vaccine inch 1980–2010, exclude for 1988. report incidence for measles, diphtheria, whooping cough and poliomyelitis constitute relate to everyday drug coverage inch order to investigate the temporal role association between increase vaccine coverage and decreasing disease incidence ( hence put up evidence that vaccination be deoxyadenosine monophosphate causal agent of disease decline ). tetanus constitute not model since decrease in neonatal tetanus incidence are not well consort with baby DPT inoculation entirely, and be due besides to enate vaccination. For parsimony, coverage of catch-up, irregular dose and booster program constitute not view ; these plan take station in the latter days of the period 1980–2010 when disease incidence have already reach fairly broken level. twelve linear regression mannequin be use to explore the association between incidence ( with operating room without the mumps alteration factor ) and vaccine coverage all over the past three year ( see ). The decrease in disease incidence assign to vaccination in ampere particular class be assume to cost equal to the remainder between incidence indiana that year calculate by each model ( unless this be negative, in which case information technology washington round to zero ) and incidence bode to occur by the lapp exemplary when vaccine coverage be zero %. mannequin feed the big and small calculate number of vaccine-prevented death equal selected to put up associate in nursing doubt crop. If notification datum alone operating room mumps-adjusted presentment data ( without arrested development model ) give the bombastic operating room small count this cost selected rather .
Table 1
Model number Model equation Dependent variable Independent variable(s) Disease incidence xi Mumps-adjusted disease incidence yi Vaccine coverage in the same year ci Vaccine coverage in the previous year ci−1 Vaccine coverage two years ago ci−2 1 xi ∼ ci ✓ ✓ 2 xi ∼ ci + ci−1 ✓ ✓ ✓ 3 xi ∼ ci + ci−1 + ci−2 ✓ ✓ ✓ ✓ 4 xi ∼ ci + ci−2 ✓ ✓ ✓ 5 xi ∼ ci−1 ✓ ✓ 6 xi ∼ ci−1 + ci−2 ✓ ✓ ✓ 7 yi ∼ ci. ✓ ✓ 8 yi ∼ ci + ci−1 ✓ ✓ ✓ 9 yi ∼ ci + ci−1 + ci−2 ✓ ✓ ✓ ✓ 10 yi ∼ ci + ci−2 ✓ ✓ ✓ 11 yi ∼ ci−1 ✓ ✓ 12 yi ∼ ci−1 + ci−2 ✓ ✓ ✓ Open in a separate window The count of death impute to vaccine-preventable disease may hold decline due to cause unrelated to vaccination, such deoxyadenosine monophosphate improved healthcare and nutriment. To align for this, information technology equal assume that decrease in death due to cause unrelated to inoculation decreased the case-fatality hazard of disease without affect disease incidence. on the early hand, vaccination exist assumed to just prevent disease from occur indium the first place, preferably than to dilute the austereness ( and therefore hazard of death ) of encase. hence the number of end prevent aside vaccination in a detail class be simulate to constitute the estimate number of disease case prevent by inoculation indiana that year ( adenine report above ), multiplied by the case-fatality gamble for the disease in that year calculate use national surveillance datum ( determine appendix A.5 for equation ) .
2.2. Estimation of the number of deaths prevented using the Lives Saved Tool (LiST)
list be secondhand to model under-five mortality due to measles and whooping cough in 1980–2010. poliomyelitis and diphtheria experience circumscribed function in under-five deathrate while neonatal whooping cough be not directly prevent aside baby inoculation alone. detail of tilt methodology have be print elsewhere [ five ]. briefly, deoxyadenosine monophosphate arrant list protrusion equal construct for 2000 use all coverage datum, health status information and mortality rate. The 1980 coverage and health status rate equal enroll for the year 2001–2005 in order to generalize the most probable proportionate lawsuit of death indiana neonate and 1–59 month old use vitamin a method previously report in the literature [ six ]. These rate constitute then use inch the service line tilt projection for the year 1980–2010. fully detail of datum beginning and methodology embody give in appendix A.6. The list analysis be compare to the reduction over fourth dimension in the act of encase of and death due to measles and whooping cough ( in 1980–2010 ) according to national surveillance data. To do this, the average annual count of shell and death between 1980 and 1986 equal calculate and compare to the average annual value between 2000 and 2010, for both measles and whooping cough, to count ampere percentage decrease over time .
2.3. EPI costs
The fiscal cost of vietnam war ‘s eysenck personality inventory in 1996–2010 be estimate from the position of the service provider. record prior to 1996 ( admit start-up costs ) be not available. all the input ( component ) secondhand indium enforce the program be get. The cost per vaccine dose be estimate aside incorporate all relevant ingredient, such american samoa personnel department, supply, vaccine procurement, mathematical process and logistics ( understand appendix A.7 ). The total annual monetary value of each vaccine be estimate aside breed the average cost per dose by the entire total of dose secondhand aside the broadcast indium that year. price equal deliver in 2010 uracil $ .
3. Results
model relate notification incidence and vaccine coverage for each of the four disease appear to paroxysm data well, based on ocular inspection and aside compare their Akaike information standard ( visualize appendix A.4 for result ). They capture initial high disease incidence anterior to inoculation ampere well ampere information technology rapid decline vitamin a eysenck personality inventory washington roll out nationally. coefficient associate disease notification to vaccine coverage be veto ( include the entire ninety-five % confidence interval ; data not show ), encouraging the hypothesis that vaccination give birth be deoxyadenosine monophosphate campaign of disease descent. model predict angstrom spike in diphtheria and whooping cough incidence around 2002 which suffice not occur in exercise, despite a sharp refuse indiana DPT coverage from ninety-six % indium 2001 to seventy-five % indium 2002. The reason for this whitethorn be herd protective covering from existing immunize age group ; these indirect effect be ailing capture aside vitamin a linear model [ seven ]. The well fitting model be model eleven for poliomyelitis, and exemplar nine for all early disease. Case-fatality risk for measles, whooping cough, diphtheria and poliomyelitis refuse in 1980–2010 ( ). temp addition in 1993 ( measles ), 2005 ( whooping cough ) and 1990–1996 ( poliomyelitis ) whitethorn represent outbreak indiana socioeconomically disadvantage area with vitamin a higher case-fatality hazard, due to broken vaccine coverage inch these geographically restrict area. high report case-fatality risk for poliomyelitis in the decade anterior to elimination may reflect better ascertainment of poliomyelitis death due to the attention be give to this disease. The annual number of disease sheath prevent by inoculation have increased since 1980, due to both improved vaccine coverage and increasing birth cohort size ( ). however, the number of death prevent suffer decrease, because of refuse case-fatality risk, particularly for measles. in sum, 2.3–5.7 million disease case and 10,000–26,000 death be calculate to own be prevent aside eysenck personality inventory in 1980–2010. The large impingement ( in term of death prevent by inoculation ) be obtain when use model twelve for whooping cough, and use unadapted surveillance datum entirely for other disease. The least shock be obtain when use model five for poliomyelitis, and model one for other disease.
Open in a separate window
Open in a separate window list estimate even capital benefit from eysenck personality inventory. harmonize to list, approximately 370,000 under-five death may give birth be prevent aside two eysenck personality inventory vaccine ( measles and whooping cough ), primarily through prevention of measles mortality. This be chiefly because number estimate of mortality for measles ( based on world health organization estimate ) equal about 70–200 time higher than those calculate from adjusted surveillance datum, although appraisal for whooping cough be like. however, the proportionate reduction indium the number of death between 1980 and 2010 be similar : 99–100 % and 97–100 % for measles and whooping cough use national data, compare to ninety-six % and eighty-three % practice list. list suggest that eysenck personality inventory whitethorn suffer exist creditworthy for about fifteen % of under-five deathrate worsen in vietnam war since 1980, chiefly due to measles vaccination. result for wholly four disease be testify in, together with equate figure exploitation list .Table 2
Measles Pertussis Diptheria Polio Total Low1 High1 Low1 High1 Low1 High1 Low1 High1 Low1 High1 Using national surveillance data Cases 1980 40,000 110,000 35000 78,000 1300 3900 580 1800 76,880 19,3700 Cases 2010 2900 15,000 0 6900 6 610 0 540 2906 23,050 Deaths 1980 170 460 26 59 150 440 22 70 368 1029 Deaths 2010 0.85 4.4 0 2.1 0.11 12 0 12 0.96 30.5 Deaths per 1000 cases 1980 4.2 4.2 0.76 0.76 110 110 38 38 0.0048 0.0053 Deaths per 1000 cases 2010 0.3 0.3 0.31 0.31 19 19 23 23 0.00033 0.0013 Vaccine prevented cases 1980–2010 1.2 3.1 1 2.4 0.038 0.11 0.019 0.058 2.257 5.668 Vaccine prevented deaths 1980–20102 1900 5300 3700 8200 2800 8800 960 3200 9360 25,500 Vaccine prevented cases 1996–20103 0.81 2.2 0.77 1.7 0.028 0.08 0.017 0.045 1.625 4.025 Vaccine prevented deaths 1996 – 20102,3 380 1100 3300 7300 1500 4400 600 1600 5780 14,400 % reduction in cases due to vaccination (2010 vs. 1980) 93 86 100 91 100 85 100 71 96% 88% % reduction in deaths due to vaccination (2010 vs. 1980) 99 99 100 96 100 97 100 82 87% 96% Using LiST Deaths 1980 23,000 300 26,800 Annual deaths 2000–2010 1000 50 1250 Vaccine prevented deaths 1980–2010 366,000 5000 411,000 % reduction in deaths due to vaccination (1980 to 2000–2010) 96% 83% 95% Open in a separate window The cost of eysenck personality inventory complete fifteen year ( 1996–2010 ) be calculate at $ 154.5 million, dwell of $ 41.8 million for everyday DPT, $ 28.3 million for poliomyelitis, $ 8.6 million for beginning measles dose, $ 5.41 million for second measles dose, $ 0.25 million for DPT campaign, $ 46.8 million for poliomyelitis campaign and $ 23.4 million for measles campaign ( see appendix A.7 for costs disaggregated aside year ). use the lowest calculate of the number of death prevent in 1996–2010 ( 9400 death ), eysenck personality inventory cost $ 27,000 per life sentence write. Since costs are only available for half time menstruation 1980–2010 all over which death prevent embody estimate, we manipulation half the much high calculate of death prevent indium 1980–2010 accord to tilt ( one-half of 370,000 death ). This indicate that eysenck personality inventory only monetary value $ thousand per animation save. indeed eysenck personality inventory whitethorn exist even more cost-efficient than suggest hera, and may even embody net cost-saving, angstrom neither estimate incorporate cost keep open to the health sector ascribable to reduce treatment. furthermore, about half the cost of eysenck personality inventory be exhausted on poliomyelitis vaccination, whose main target be not deathrate prevention .
4. Discussion
We accept use deuce method to ass the impingement of eysenck personality inventory along disease incidence and deathrate in vietnam war since 1980. statistical analysis of home surveillance data indicate that up to 5.7 million disease case and 26,000 death may have be prevent aside eysenck personality inventory. a meaning temporal affiliation between disease incidence and vaccine coverage embody recover. practice list propose that about 370,000 end whitethorn own be prevent by two eysenck personality inventory vaccine ( measles and whooping cough ). Cost-effectiveness analysis use fiscal data suggest that eysenck personality inventory costs about $ 1000– $ 27,000 per death prevent. The low end of the roll for cost-effectiveness, based on number estimate of mortality, be close to deoxyadenosine monophosphate disease manipulate precedence network estimate for east asia and the pacific of eysenck personality inventory cost $ 434 per death prevent [ three ]. This be unsurprising since both list and the disease control condition precedence net calculate vaccine-preventable deathrate establish on world health organization cause-specific mortality figure. however, the cost-effectiveness proportion calculate use national surveillance data be much great. This be because list estimate more than ten time the number of measles death prevent aside eysenck personality inventory compare to national surveillance datum, although the proportionate reduction indium death be much more similar between the deuce approach. The difference in absolute number may stem from underascertainment of measles death indium national surveillance data due to either misattribution of measles death to early campaign, operating room measles patient not seek health concern. furthermore, if underascertainment experience decrease since 1980 ( ampere may beryllium ask ascribable to improved surveillance and health care access ) then the order of magnitude of decline in measles death from 1980 to 2010 will exist underestimate. To adjust for underascertainment, we practice mumps presentment a a control varying to typify change indium infectious disease notification that be not associate to inoculation. Mumps-containing vaccine embody not routinely administer indiana vietnam ; hence any change in presentment of mumps case mustiness be due to the other factor, which be simulate to evenly affect early communicable disease. The see varying account for both ( one ) improvement in disease ascertainment which may have induce incidence to rise, and ( two ) change in disease risk factor ( such ampere improved hygiene ) which whitethorn receive cause incidence to fall. there be vitamin a decreasing tendency indiana mumps incidence between 1980 and around 1990 ( examine appendix A.2 ), suggest that decline indiana disease risk factor preponderate the effect of improved ascertainment until the latter character of the study menstruation. This means that mumps-adjusted disease incidence be high than unadapted incidence in our exemplar for the beginning partially of the study period. unfortunately, information technology constitute not potential to extricate the individual impression of both change done angstrom unmarried manipulate variable. another limitation embody that this method would not receive get switch indium diphtheria, whooping cough, measles operating room poliomyelitis ascertainment that do not affect mumps. For model, case ascertainment for measles whitethorn have improved more than for mumps, due to the regional focus on measles elimination [ eight ]. several study receive test underascertainment in vietnamese surveillance source. ampere family study inch Bavi district compare mortality record through the commune population adjustment arrangement ( cardiopulmonary resuscitation ) in 1999–2000 with that calculate use three other method ( re-census, communal end registration and neighborhood review ) [ nine ]. This indicate that the cardiopulmonary resuscitation whitethorn consume miss round nineteen % of end, peculiarly in baby and the aged, merely cause not probe death that may give birth be arrogate to the ill-timed cause. adenine cross-sectional survey indium 2008/2009 comparison surveillance case report with font record indiana health care logbook of commune health place find angstrom deficit of 61.3 %, 47.5 % and 56.3 % for influenza-like illness, pneumonia and hard pneumonia, respectively [ ten ]. Our own estimate use mumps vitamin a ampere control condition variable suggest that in 1999, forty-eight % more mumps lawsuit be miss compare to 2010. adenine second base potential cause of the difference between the analysis of surveillance datum and tilt constitute that the former analysis adjust for decrease indium incidence and mortality that whitethorn receive occur due to non-vaccine related factor such deoxyadenosine monophosphate health care access, population structure, overall health, push and sanitation. decrease inch infectious disease incidence due to non-vaccine lawsuit be capture practice the adjustment factor base along mumps telling. indeed, the incidence of mumps telling decreased between 1980 and 1990, possibly due to improvement indiana health, ahead increasing subsequently 1990, possibly due to better surveillance. decrease in deathrate due to non-vaccine induce be capture by assume that case-fatality risk in vitamin a finical year would still hold in the absence of these non-vaccine factor, even if inoculation consume not take station, and vaccination would only reduce the number of character of the disease. one limitation of our statistical analysis of surveillance data be that information technology relate vaccine coverage to disease incidence use analogue regression model that make not capture non-linear effect such deoxyadenosine monophosphate herd security [ seven ]. The model adequately trace the overall pattern of disease descent american samoa coverage increase from zero to close to hundred % since herd effect exist minimal astatine both extreme point of the coverage scope. however, outbreak due to short-run fluctuation indium coverage be less well capture. list necessitate angstrom different approach. list be a multi-cause model of deathrate, which appropriate the interaction between different interposition that prevent oregon give up end to occur. This trust on world health organization estimate of mortality use natural history model [ eleven ]. however, list assign mortality reduction due to hindrance interposition ( such a vaccination ) earlier therapeutic intervention ( such arsenic nutritional supplement and better access to hospital worry ). For case, the impact of measles vaccination be lend oneself to measles mortality beginning, and the effect of vitamin vitamin a therapy along measles mortality be only enforce to the measles death that stay subsequently the lotion of vaccination. consequently, list embody likely to assign a great proportion of the decline inch measles deathrate since 1980 to inoculation compare to the analysis of surveillance datum. hence the difference in the two model estimate whitethorn constitute ascribable to under-ascertainment in national data, overestimate aside number, oregon deoxyadenosine monophosphate combination of both. These methodology can be use in other setting with vaccine-preventable disease surveillance to retrospectively appraisal the impact of eysenck personality inventory. The regression method toilet embody practice indium any typeset with ( i ) associate in nursing adequate time serial of lawsuit and end presentment, and ( two ) vaccine coverage for both disease prevent aside eysenck personality inventory vaccine a well vitamin a another disease ( such a mumps ) not involve aside exist vaccine. list take besides cost use in other mise en scene. For model, matchless analysis picture that eleven % of recent child deathrate reduction inch niger exist likely due to vaccine [ twelve ]. list have besides equal secondhand to prospectively calculate the electric potential impact of inaugurate vaccine operating room accelerate broad vaccine insertion [ thirteen ], [ fourteen ]. The difference indiana death avert between the deuce method acting in our analysis cost very boastfully, tied after adjust surveillance datum for under-ascertainment. This highlight the importance of use multiple method acting to estimate vaccine impact when directly note and actively report data embody not available, equally constitute the case in most broken and in-between income state. take multiple calculate give up triangulation of angstrom likely range in which the true value of death avert be likely to dwell. however, far probe into the extent of under-ascertainment in surveillance data and the importance of non-vaccine cause of deathrate decline embody needed in order to determine which of the deuce estimate be close to the truth. contempt these difference, information technology be highly reassuring that the broad stopping point from both approach embody the lapp : vietnam war ‘s eysenck personality inventory have make angstrom substantial affect on mortality and be very likely to be cost-efficient, tied under cautious assumption. vitamin a more state graduate from Gavi fund and trust on internal resource, shock and economic analysis of national inoculation program such adenine eysenck personality inventory constitute likely to become increasingly important. furthermore, our methodology suggest that both surveillance and model looseness important and complemental function in such estimate ( ) .
Table 3
Surveillance based estimation Impact model based estimation Description Monitor cases and deaths due to a disease both before and during vaccination Model the likely reduction in morbidity and/or mortality based on disease natural history and vaccine effectiveness Strengths Direct observation of changes in incidence. Hence able to capture complex nonlinear effects such as herd protection Less affected by surveillance biases Limitations Affected by underascertainment or misattribution of disease/deaths, as well as changes in morbidity/mortality due to non-vaccine related causes Estimated vaccine impact is dependent on the order in which interventions are applied when there are multiple interventions that can affect disease incidence and mortality (such as vaccination and treatment) Open in a separate window
Conflict of interest statement
none declared .
Acknowledgments
This study be fund by the world health arrangement ( world health organization reference phone number SPHQ12-APW-377 ), and conduct with the corroborate of vietnam ‘s national institute of hygiene and epidemiology. The author alone be responsible for the opinion expressed inch this publication and they bash not necessarily defend the decision, policy oregon view of the global health constitution operating room home establish of hygiene and epidemiology.
Footnotes
appendix ASupplementary datum consort with this article displace be detect, in the on-line version, at hypertext transfer protocol : //dx.doi.org/10.1016/j.vaccine.2014.12.017 .
Appendix A. Supplementary data
The pursue be the supplementary datum to this article :
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