Distribution of insecticide-treated bednets during an integrated nationwide immunization campaign--Togo, West Africa, December 2004

During December 13-19, 2004, Togo, a West African nation with a population of approximately 5 million, conducted the first-ever nationwide distribution of insecticide-treated bednets (ITNs) for prevention of malaria. A supplemental immunization activity (SIA), conducted as part of Togo's measles mortality reduction strategy and targeting all children aged 9-59 months, was used as an opportunity to distribute ITNs, oral poliovirus vaccine (OPV), and the anti-helminthic medication, mebendazole. The campaign aimed to achieve >95% coverage among the 866,725 children aged 9-59 months with measles vaccine, OPV, one ITN, and one tablet of mebendazole. This report describes the planning, implementation, and results of this campaign, with emphasis on ITN distribution. The findings demonstrate the feasibility of integrating delivery of these services in a campaign setting.     

Distributing insecticide-treated bednets during measles vaccination: a low-cost means of achieving high and equitable coverage

OBJECTIVE: To achieve high and equitable coverage of insecticide-treated bednets by integrating their distribution into a measles vaccination campaign. METHODS: In December 2002 in the Lawra district in Ghana, a measles vaccination campaign lasting 1 week targeted all children aged 9 months-15 years. Families with one or more children less than five years old were targeted to receive a free insecticide-treated bednet. The Ghana Health Service, with support from the Ghana Red Cross and UNICEF, provided logistical support, volunteer workers and social mobilization during the campaign. Volunteers visited homes to inform caregivers about the campaign and encourage them to participate. We assessed pre-campaign coverage of bednets by interviewing caregivers leaving vaccination and distribution sites. Five months after distribution, a two-stage cluster survey using population-proportional sampling assessed bednet coverage, retention and use. Both the pre-campaign and post-campaign survey assessed household wealth using an asset inventory. FINDINGS: At the campaign exit interview 636/776 (82.0%) caregivers reported that they had received a home visit by a Red Cross volunteer before the campaign and that 32/776 (4.1%) of the youngest children in each household who were less than 5 years of age slept under an insecticide-treated bednet. Five months after distribution caregivers reported that 204/219 (93.2%) of children aged 9 months to 5 years had been vaccinated during the campaign; 234/248 (94.4%) of households were observed to have an insecticide-treated bednet; and 170/249 (68.3%) were observed to have a net hung over a bed. Altogether 222/248 (89.5%) caregivers reported receiving at least one insecticide-treated bednet during the campaign, and 153/254 (60.2%) said that on the previous night their youngest child had slept under a bednet received during the campaign. For households in the poorest quintile, post-campaign coverage of insecticide-treated bednets was 10 times higher than pre-campaign coverage of households in the wealthiest quintile (46/51 (90.2%) versus 14/156 (9.0%)). The marginal operational cost was 0.32 US dollars per insecticide-treated bednet delivered. CONCLUSION: These findings suggest that linking bednet distribution to measles vaccination campaigns may provide an important opportunity for achieving high and equitable coverage of bednets.     

Assessment of vaccine wastage during a pulse polio immunization programme in India

A study to assess the wastage factor of oral polio vaccine (OPV) in the Pulse Polio Immunization (PPI) programme of the Government of India was undertaken by the Indian Council of Medical Research (ICMR) at approximately 31,000 immunization booths all over the country. The study was conducted through the network of 31 Human Reproduction Research Centres (HRRCs) and other ICMR institutes. Wastage at the point of administration of OPV was estimated to be 14.5% with a wastage factor of 1.17 which is well below the assumed wastage of 33% and the corresponding wastage factor of 1.5 in the PPI programme. The wastage and wastage factor as estimated in the present study were also less than the wastage of 25% and the wastage factor of 1.33 recommended by the World Health Organization. Minimum wastage (6.3%) at Kanchipuram and maximum wastage (22.1%) at Kanpur were observed. Further, the wastage of unopened vials and vials during use was also observed following colour changes on the vaccine vial monitor (VVM), indicating poor cold-chain maintenance at the immunization site. In total, 13 booths reported wastage of nine or more unopened vials, whereas 19 booths reported wastage of nine or more vials during use because of colour changes on VVM. Other reasons for wastage of vaccine were also observed from a sample of booths. The technology of introducing VVM on OPV vials for monitoring the cold-chain proved useful in situations in which mass vaccination programmes such as PPI are carried out.     

Effects of insecticide-treated bednets during early infancy in an African area of intense malaria transmission: a randomized controlled trial

OBJECTIVE: Insecticide-impregnated bednets and curtains have been shown by many studies to be effective against malaria. However, because of possible interactions with immunity development, treated bednets may cause no effect at all or even an increase in malaria morbidity and mortality in areas of high transmission. To clarify this issue, we did a randomized controlled trial to assess the long-term effects of bednet protection during early infancy. METHODS: A total of 3387 neonates from 41 villages in rural Burkina Faso were individually randomized to receive either bednet protection from birth (group A) or from age 6 months (group B). Primary outcomes were all-cause mortality in all study children and incidence of falciparum malaria in a representative subsample of the study population. FINDINGS: After a mean follow-up of 27 months, there were 129 deaths in group A and 128 deaths in group B rate ratio (RR) 1.0 (95% confidence interval (CI): 0.78-1.27)). Falciparum malaria incidence was lower in group A than in group B, during early (0-5 months) and late infancy (6-12 months) (RR 3.1, 95% CI: 2.0-4.9; RR 1.3, 95% CI: 1.1-1.6) and rates of moderate to severe anaemia were significantly lower during late infancy (11.5% vs 23.3%, P = 0.008), but there were no differences between groups in these parameters in children older than 12 months. CONCLUSION: The findings from this study provide additional evidence for the efficacy of insecticide-treated nets in young children living in areas of intense malaria transmission.     

Evidence for a mass community effect of insecticide-treated bednets on the incidence of malaria on the Kenyan coast

The use of insecticide-treated bednets (ITBNs) has been shown to be effective in reducing mortality and morbidity from malaria. However, there is mixed evidence as to whether or not community-wide use of ITBNs engenders a 'mass effect', such that those not sleeping under bednets are offered protection from widespread ITBN use in the area in which they live. We have analysed data collected in Kilifi, Kenya, from a cohort of children followed from birth to investigate how the degree of net usage in the locality of a child affects the risk of developing malaria. This effect was explored using a Cox proportional hazards model. For those not using ITBNs, we found that an increasing level of ITBN usage within the area surrounding each child was associated with a decreasing risk of developing malaria, thus providing evidence in support of a mass community effect. The size and significance of this effect were found to decrease as non-overlapping areas of increasing distance away from a child's home were considered. The effect was significant for areas at distances of up to 1.5 km away from each child.     

Mass use of insecticide-treated bednets in malaria endemic poor countries: public health concerns and remedies

Epidemiological evidence arising mainly from studies undertaken in sub-Saharan Africa suggests that sleeping under insecticide-treated mosquito nets is a cost-effective and efficacious method of controlling malaria. For this reason, promotion of use of insecticide-treated nets (ITNs) has become a key malaria control strategy. In 1999, the United Nations Children's Fund (UNICEF) and WHO set the goal of providing 32 million nets and 320 million net treatments a year for the next 10 years to protect 80% of African households against malaria. All pesticides are toxic by nature and are associated with adverse health risks that depend on the toxicity of each chemical, as well as the type and degree of exposure. Thus, massive scale-up of use of ITNs in malaria endemic poor countries can be expected to present tangible risks to health, especially where the insecticides for net treatment and re-treatment are handled mostly by untrained persons in uncontrolled settings. This paper examines potential health risks of mass use of ITNs in malaria endemic poor countries and calls for the implementation of strategies to minimize potential risks through careful selection of products, appropriate labeling (including labeling in the local languages of the user communities), pesticide safety education of the public and training of health personnel, and active monitoring of adverse health effects to document actual and potential hazards, and to facilitate planning of mitigation efforts.     

Prevention of anaemia in pregnancy using insecticide-treated bednets and sulfadoxine-pyrimethamine in a highly malarious area of Kenya: a randomized controlled trial

To compare the effects of intermittent treatment with sulfadoxine-pyrimethamine (SP) given during the second and third trimester of pregnancy, the use of insecticide-treated nets (ITN), or the combination of both on haemoglobin (Hb) levels during pregnancy, a randomized, placebo-controlled intervention trial was conducted in a malaria-endemic area of western Kenya from July 1997 to September 1999. Primigravidae and secundigravidae were enrolled into the study and randomized into 4 intervention groups: (i) ITNs and SP, (ii) ITNs and placebo SP, (iii) SP alone, and (iv) placebo SP. All groups were offered case management and iron and folic acid supplementation. Seven hundred and fifty-two women were followed until delivery (53.2% were primigravidae and 46.8% secundigravidae). Among primigravidae in all the groups there was a significant improvement in Hb levels at delivery (107.6 g/L) compared with recruitment (101.9 g/L) (P < 0.006) with the greatest improvement in the combination ITNs + SP group. The protective efficacy of ITNs + SP on anaemia was 55.8% (95% CI 30.6-71.8), of SP alone 50.9% (95% CI 22.2-69.0), and of ITNs 41.6% (95% CI 9.8-62.3). Among secundigravidae, Hb levels were slightly lower at delivery compared with recruitment (P = 0.03). It was concluded that malaria is a major cause of anaemia in primigravidae but that other causes play a more significant role in secundigravidae, and that intermittent treatment with SP or use of ITNs benefits primigravidae more than secundigravidae.     

广东省2003～2004年脊髓灰质炎疫苗强化免疫活动效果分析

目的 了解广东省2003～2004年脊髓灰质炎(脊灰)疫苗强化免疫活动效果。方法 按强化免疫活动实施方案于2003年12月5～6日和2004年1月5～6日在广东省全省范围开展脊灰疫苗强化免疫活动,逐级进行资料汇总上报,并采用随机原则进行现场快速评估。结果 全省各地上报第一轮应接种对象2701029人,已接种2625039人,接种率为97．2％;第二轮应接种对象2769745人,已接种2693545人,接种率为97．2％。现场快速评估,第一轮共调查7947名对象,接种率为97．1％,上卡率为92．9％;第二轮共调查7539名对象,接种率为98．2％,上卡率为94．1％。结论 两轮强化免疫活动的脊髓灰质炎疫苗接种率均达到95％以上的目标。今后应继续加强对流动儿童的免疫接种工作。     

Costs of polio immunization days in China: implications for mass immunization campaign strategies

Ten provinces of China were selected to estimate the cost per immunization of the 1994-95 national immunization days (NIDs) at five levels (e.g. province, prefecture, county, township and village). Personnel costs accounted for the largest overall share of costs (39 per cent), followed by publicity and promotion costs (27 per cent), and logistic costs (15 per cent). Without consideration of vaccine costs, the major part of NID expenses were shouldered at the township level, which paid for 47 per cent of all incremental costs, while county and village level covered 28 per cent and 18 per cent respectively. Estimation of average costs per immunization was 2.86 RMB yuan, or $0.34, including vaccine costs, buildings and equipment amortization and salaries at all levels. The factors affecting average cost of NID included the output volume, socio-economic development and geographic features. Various approaches were recommended: to intensify the productivity of time and staff, to employ alternative inexpensive manpower resources, to make the best use of publicity and social promotion, the expansion of the age groups and utilization of multi-intervention strategies. Good planning at township level was a decisive factor to ensure an effective NID conducted in an efficient manner. The average cost of China's NID was the lowest among all mass immunization campaigns ever documented. Much of the reduced average cost was attributable to economies of scale.     

Assessing the potency of oral polio vaccine kept outside of the cold chain during a national immunization campaign in Chad

This study is the first systematic documentation of the potency of monovalent oral polio vaccine type 3 (mOPV3) kept at ambient temperatures during a polio immunization campaign in Chad. During the study test vials were exposed to temperatures of up to 47.1 °C, and kept outside of the 2-8 °C range for a maximum of 86.9 hours. Post-campaign laboratory testing confirmed that the test vials were still potent, and in conformity with the defined release specifications. Further, the Vaccine Vial Monitors performed as expected, giving an early warning indication of when cumulative exposure to heat reached levels that may have negatively affected the vaccine's potency. This study provides proof-of-concept evidence that certain types of OPV remain potent and thus can be kept, for limited periods of time, as well as administered at ambient temperatures.     

The cost-effectiveness of alternative polio immunization policies in South Africa

AIMS: To assess the cost-effectiveness of switching from oral polio vaccine (OPV) to inactivated poliovirus vaccine (IPV), or to cease polio vaccination in routine immunization services in South Africa at the time of OPV cessation globally following polio eradication. METHODS: The cost-effectiveness of nine different polio immunization alternatives were evaluated. The costs of introducing IPV in a separate vial as well as in different combination vaccines were estimated, and IPV schedules with 2, 3 and 4 doses were compared with the current 6-dose OPV schedule. Assumptions about IPV prices were based on indications from vaccine manufacturers. The health impact of OPV cessation was measured in terms of vaccine associated paralytic paralysis (VAPP) cases and disability adjusted life years (DALYs) averted. CONCLUSIONS: The use of OPV in routine immunization services is predicted to result in 2.96 VAPP cases in the 2005 cohort. The cost-effectiveness of the different IPV alternatives varies between US$ 740,000 and US$ 7.2 million per VAPP case averted. The costs per discounted DALY averted amount to between US$ 61,000 and US$ 594,000. Among the IPV strategies evaluated, the 2-dose schedule in a 10-dose vial is the most cost-effective option. At the assumed vaccine prices, all IPV options do not appear to be cost-effective in the South African situation. OPV cessation without IPV replacement would result in cost savings of US$ 1.6 million per year compared to the current situation. This is approximately a 9% decrease in the budget for vaccine delivery in South Africa. However, with this option there is a risk (albeit small) of vaccine-derived poliovirus circulating in a progressively susceptible population. For IPV in a single dose vial, the break-even price, at which the costs of IPV delivery equal the current OPV delivery costs, is US$ 0.39.     

The role of routine polio immunization in the post-certification era

The role of routine vaccination against poliomyelitis for the post-certification era remains an important area for policy decision-making. Two critical decisions need to be taken: first, to continue or discontinue vaccination with the live attenuated oral poliovirus vaccine (OPV); and second, if OPV is to be discontinued, whether vaccination with inactivated poliovirus vaccine (IPV) is needed. Four potential vaccination scenarios can be constructed: stop all polio vaccination; continue with current vaccination policies (OPV, IPV, or sequential schedule); discontinue OPV, but continue IPV universally; or discontinue OPV, but continue IPV in selected countries. All possible scenarios require continued investments in a surveillance and response strategy, including a stockpile of polio vaccine. Continuing vaccination would limit the savings that could be applied to the control of other health priorities. This report reviews the key issues associated with each scenario, highlights the advantages and disadvantages of each scenario, and outlines the major challenges for policy decision-making.     

Supplementary polio immunization activities and prior use of routine immunization services in non-polio-endemic sub-Saharan Africa

Objective

To determine participation in polio supplementary immunization activities (SIAs) in sub-Saharan Africa among users and non-users of routine immunization services and among users who were compliant or non-compliant with the routine oral poliovirus vaccine (OPV) immunization schedule.

Methods

Data were obtained from household-based surveys in non-polio-endemic sub-Saharan African countries. Routine immunization service users were children (aged < 5 years) who had ever had a health card containing their vaccination history; non-users were children who had never had a health card. Users were considered compliant with the OPV routine immunization schedule if, by the SIA date, their health card reflected receipt of required OPV doses. Logistic regression measured associations between SIA participation and use of both routine immunization services and compliance with routine OPV among users.

Findings

Data from 21 SIAs conducted between 1999 and 2010 in 15 different countries met inclusion criteria. Overall SIA participation ranged from 70.2% to 96.1%. It was consistently lower among infants than among children aged 1–4 years. In adjusted analyses, participation among routine immunization services users was > 85% in 12 SIAs but non-user participation was > 85% in only 5 SIAs. In 18 SIAs, participation was greater among users (P < 0.01 in 16, 0.05 in 1 and < 0.10 in 1) than non-users. In 14 SIAs, adjusted analyses revealed lower participation among non-compliant users than among compliant users (P < 0.01 in 10, < 0.05 in 2 and < 0.10 in 2).

Conclusion

Large percentages of children participated in SIAs. Prior use of routine immunization services and compliance with the routine OPV schedule showed a strong positive association with SIA participation.     

Attitudes and perceptions of private pediatricians regarding polio immunization in India

Background

India has faced considerable challenges in eradicating polio. Uttar Pradesh (UP) and Bihar are the two states in India where transmission of polio has never been interrupted. Private pediatricians are important stakeholders for vaccine delivery and maintaining public confidence in vaccines. The purpose of this study was to investigate the attitudes and perceptions of pediatricians in India regarding polio immunization and their opinions about various strategies regarding polio eradication in the country.

Methods

A random sample of 785 pediatricians belonging to the Indian Academy of Pediatrics (IAP) were selected for the survey with over sampling of members located in Bihar and UP. Potential participants were either contacted by phone or sent a self-administered anonymous questionnaire by mail. For this analysis both sets of responses were combined. Surveys were conducted from June 2009 to June 2010.

Results

A total of 398 surveys were completed (51%). Nearly all respondents indicated that polio eradication is still an important priority (99.7%). Ninety-six percent of pediatricians believed that strengthening routine immunization efforts remains the best way to eradicate polio in endemic areas. Other measures thought to be important in eradicating polio are mass campaigns with IPV (73%) and mass campaigns with bivalent OPV (59%). Pediatricians also identified several barriers to polio eradication which included parents’ lack of awareness of the importance of polio vaccination (88.8%), parents’ lack of confidence in polio vaccine (64.0%), religious beliefs (59.2%), fear of side effects (59.2%), lack of time or priority (56.6%), superstition (50.3%) and cultural beliefs (46.4%).

Conclusion

There is still strong support for polio eradication efforts among IAP members. Pediatricians in India strongly believe that improving the coverage of routine immunization remains the best way to eradicate polio. There is an urgent need to improve awareness, build confidence in the program, and remove barriers among parents.     

Clustered lot quality assurance sampling: a tool to monitor immunization coverage rapidly during a national yellow fever and polio vaccination campaign in Cameroon, May 2009

We used the clustered lot quality assurance sampling (clustered-LQAS) technique to identify districts with low immunization coverage and guide mop-up actions during the last 4 days of a combined oral polio vaccine (OPV) and yellow fever (YF) vaccination campaign conducted in Cameroon in May 2009. We monitored 17 pre-selected districts at risk for low coverage. We designed LQAS plans to reject districts with YF vaccination coverage <90% and with OPV coverage <95%. In each lot the sample size was 50 (five clusters of 10) with decision values of 3 for assessing OPV and 7 for YF coverage. We 'rejected' 10 districts for low YF coverage and 14 for low OPV coverage. Hence we recommended a 2-day extension of the campaign. Clustered-LQAS proved to be useful in guiding the campaign vaccination strategy before the completion of the operations.     

Immunologic memory induced at birth by immunization with inactivated polio vaccine in a reduced schedule

Abstract of inactivated polio vaccine (IPV) of enhanced potency. Following the administration of a second vaccine dose six months later, a considerable proportion of babies responded with neutralizing antibody (NA) to the three poliovirus types. The very rapid occurrence and high antibody titer were indicative of an anamnestic response. Twenty-one infants who still had NA < 1:4 to one-more poliovirus types after the second vaccine dose responded with very high NA values 7–10 days after a supplementary dose of IPV. It appears that IPV of enhanced potency administered at birth is apt to induce immunologic memory, which should provide the basis for protection against paralytic poliomyelitis in case of exposure to wild poliovirus later in life.