I. Adetifa, KEMRI-Wellcome Trust Research Programme, Kenya, Seroepidemiology for monitoring vaccination and informing vaccine policy in Africa

I. Adetifa，KEMRI-Wellcome 信托研究计划，肯尼亚，用于监测非洲疫苗接种和通报疫苗政策的血清流行病学

• 批准号: MR/S005293/1
• 负责人: J Scott
• 金额: $ 96.63万
• 依托单位: London School of Hygiene & Tropical Medicine
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FS005293%2F1
• 关键词: I.; Adetifa; KEMRI; Wellcome; Trust

Although vaccines are essential for preventing many severe and often fatal diseases, they are only beneficial when received so their impact is greatly dependent achieving high vaccination coverage. Consequently, vaccination coverage indices are widely used to monitor vaccination programmes. Vaccination coverage is commonly assessed as the proportion of children aged 12-23 months who received the 3rd dose of a diphtheria-pertussis-tetanus (DPT3)-containing vaccine at age 12 months. DPT3 coverage is typically obtained from administrative records (registers in vaccine clinics and records of total doses of vaccines consumed). It can be also obtained from household surveys of vaccine cards/records or by asking caregivers to confirm vaccination by memory recall. Coverage estimates obtained from administrative records frequently overestimate coverage in low and middle-income countries because of errors in tracking consumption of vaccine doses and wrongly estimated target population. While survey methods provide more accurate estimates, they are disruptive to routine health services and expensive. Other weaknesses are incomplete representation of the target population, underreporting, and missing and/or incomplete information. It is important to for estimates of vaccination coverage to be as accurate as possible especially as receiving a vaccine i.e. vaccination does not always result in immunisation which is defined as vaccine-induced protection against the targeted disease. For example, following measles vaccination, the proportions of children who develop protective antibody levels are approximately 85% at 9 months of age and 95% at 12 months of age. Conventional methods for measuring coverage do not tell us what proportion of the population has immunity against the disease of interest. In high income countries, national serological surveys are conducted to obtain blood samples to measure the proportion of the population that is protected by vaccination. These blood samples are tested for antibodies produced in response to vaccines. As a result, these countries have a longer experience of using these antibody surveys to estimate the burden of diseases before introducing vaccines and assessing the performance of vaccination programmes in reducing disease burden e.g. for hepatitis B. These antibody surveys are also used to identify at-risk groups requiring special vaccination programmes e.g.mass campaigns, and to assess the duration of vaccine induced protection. Serosurveys require reliable vaccination records which are typically available in developed countries. In the developing countries of Africa, I found very limited use of serological surveys to monitor vaccination and to guide revisions of vaccination strategies as seen in high income countries. However, I found that testing for antibodies induced by tetanus vaccine may be useful for this purpose because it overcomes one key limitation of serological surveys i.e. distinguishing between antibodies from natural infection and those resulting from vaccination. I will investigate the possibility of using antibody testing to monitor vaccination and to compare this to vaccine records in Kilifi, extend this experience to samples from a nationwide survey. This project will benefit from the excellent opportunities provided by the availability of serum samples collected during serological surveys in Kilifi from 2009-2017 and reliable vaccine records from the Kilifi vaccine registry. I will apply statistical methods to antibody test results to identify a reliable mathematic model that reliably predicts vaccination coverage when compared to vaccine records. On identifying this model, I will then carry out a nationwide serological survey, apply the methods validated in Kilifi to the antibody test results to estimate national vaccination coverage, identify at-risk populations with gaps in their immunity and make recommendations for interventions to protect these populations.

尽管疫苗对于预防许多严重且往往致命的疾病至关重要，但只有接种疫苗才有益，因此其影响在很大程度上取决于实现高疫苗接种覆盖率。因此，疫苗接种覆盖率指数被广泛用于监测疫苗接种规划。疫苗接种覆盖率通常以12-23个月大的儿童在12个月大时接种第三剂白喉-百日咳-破伤风（DPT3）疫苗的比例来评估。白喉三联疫苗的覆盖率通常从行政记录（疫苗诊所的登记和所消耗的疫苗总剂量记录）中获得。它也可以通过对疫苗卡/记录的家庭调查或通过要求护理人员通过回忆来确认接种疫苗来获得。从行政记录中获得的覆盖率估计经常高估低收入和中等收入国家的覆盖率，原因是在跟踪疫苗剂量消费方面存在错误，以及对目标人群的估计有误。虽然调查方法提供了更准确的估计，但它们扰乱了常规卫生服务，而且费用昂贵。其他弱点是目标人群的不完全代表、少报、缺失和/或不完整的信息。重要的是，对疫苗接种覆盖率的估计要尽可能准确，特别是在接种疫苗（即接种疫苗）并不总是导致免疫接种的情况下，免疫接种被定义为疫苗引起的针对目标疾病的保护。例如，接种麻疹疫苗后，在9个月大时产生保护性抗体水平的儿童比例约为85%，在12个月大时达到95%。衡量覆盖率的传统方法并不能告诉我们有多少比例的人口对所关注的疾病具有免疫力。在高收入国家，进行全国血清学调查以获取血液样本，以衡量受疫苗接种保护的人口比例。对这些血液样本进行检测，以检测对疫苗产生的抗体。因此，这些国家在采用疫苗和评估疫苗接种规划在减轻疾病负担（如乙型肝炎）方面的效果之前，使用这些抗体调查来估计疾病负担的经验较长。这些抗体调查还用于确定需要特别疫苗接种规划（如大规模运动）的危险群体，并评估疫苗引起保护的持续时间。血清调查需要可靠的疫苗接种记录，这在发达国家通常可以获得。在非洲发展中国家，我发现血清学调查在监测疫苗接种和指导疫苗接种战略修订方面的应用非常有限，就像在高收入国家看到的那样。然而，我发现检测破伤风疫苗诱导的抗体可能对这一目的有用，因为它克服了血清学调查的一个关键限制，即区分来自自然感染的抗体和来自疫苗接种的抗体。我将调查利用抗体检测监测疫苗接种的可能性，并将其与基利菲的疫苗记录进行比较，将这一经验推广到全国调查的样本中。2009-2017年在基利菲进行血清学调查期间收集的血清样本的可用性以及基利菲疫苗登记处提供的可靠疫苗记录将为该项目提供极好的机会。我将对抗体测试结果应用统计方法，以确定一个可靠的数学模型，与疫苗记录相比，该模型可以可靠地预测疫苗接种覆盖率。在确定这一模式后，我将开展一项全国血清学调查，将Kilifi验证的方法应用于抗体检测结果，以估计全国疫苗接种覆盖率，确定免疫存在差距的高危人群，并就保护这些人群的干预措施提出建议。

项目成果

The cost of illness for childhood clinical pneumonia and invasive pneumococcal disease in Nigeria.

• DOI: 10.1136/bmjgh-2021-007080
• 发表时间: 2022-01
• 期刊: BMJ global health
• 影响因子: 8.1
• 作者: Adamu AL;Karia B;Bello MM;Jahun MG;Gambo S;Ojal J;Scott A;Jemutai J;Adetifa IM
• 通讯作者: Adetifa IM

Inequities in childhood immunisation coverage associated with socioeconomic, geographic, maternal, child, and place of birth characteristics in Kenya.

• DOI: 10.1186/s12879-021-06271-9
• 发表时间: 2021-06-11
• 期刊: BMC infectious diseases
• 影响因子: 3.7
• 作者: Allan S;Adetifa IMO;Abbas K
• 通讯作者: Abbas K

COVID-19 transmission dynamics underlying epidemic waves in Kenya.

• DOI: 10.1126/science.abk0414
• 发表时间: 2021-11-19
• 期刊: Science (New York, N.Y.)
• 作者: Brand SPC;Ojal J;Aziza R;Were V;Okiro EA;Kombe IK;Mburu C;Ogero M;Agweyu A;Warimwe GM;Nyagwange J;Karanja H;Gitonga JN;Mugo D;Uyoga S;Adetifa IMO;Scott JAG;Otieno E;Murunga N;Otiende M;Ochola-Oyier LI;Agoti CN;Githinji G;Kasera K;Amoth P;Mwangangi M;Aman R;Ng'ang'a W;Tsofa B;Bejon P;Keeling MJ;Nokes DJ;Barasa E
• 通讯作者: Barasa E

Inequities in childhood immunisation coverage associated with socioeconomic, geographic, maternal, child, and place of birth characteristics in Kenya

肯尼亚儿童免疫覆盖率与社会经济、地理、孕产妇、儿童和出生地特征相关的不平等

• DOI: 10.1101/2021.02.14.21251721
• 发表时间: 2021
• 作者: Allan S

The Lancet Nigeria Commission: investing in health and the future of the nation.

• DOI: 10.1016/s0140-6736(21)02488-0
• 发表时间: 2022-03-19
• 期刊: Lancet (London, England)
• 作者: Abubakar I;Dalglish SL;Angell B;Sanuade O;Abimbola S;Adamu AL;Adetifa IMO;Colbourn T;Ogunlesi AO;Onwujekwe O;Owoaje ET;Okeke IN;Adeyemo A;Aliyu G;Aliyu MH;Aliyu SH;Ameh EA;Archibong B;Ezeh A;Gadanya MA;Ihekweazu C;Ihekweazu V;Iliyasu Z;Kwaku Chiroma A;Mabayoje DA;Nasir Sambo M;Obaro S;Yinka-Ogunleye A;Okonofua F;Oni T;Onyimadu O;Pate MA;Salako BL;Shuaib F;Tsiga-Ahmed F;Zanna FH
• 通讯作者: Zanna FH