ORCID Profile
0000-0001-7081-6273
Current Organisation
National Institute for Communicable Diseases
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Publisher: Cold Spring Harbor Laboratory
Date: 08-11-2022
DOI: 10.1101/2022.11.07.22282045
Abstract: Invasive pneumococcal disease (IPD) risk increases with age for older adults whereas the population size benefiting from pneumococcal vaccines and the robustness of the immunogenic response to vaccination decline. This poses a conundrum for identifying the optimal age for vaccination. We estimate how demographics, vaccine efficacy/effectiveness (VE), and waning VE impact on optimal age for single-dose pneumococcal vaccination. Age- and vaccine-serotype-stratified IPD incidence from routine surveillance of adults ≥55 years old (y) in Brazil, England, Blantyre (Malawi), and South Africa, ≥4-years after infant-pneumococcal vaccine introduction and before 2020, was used to parameterise exponential growth models of increasing IPD risk with age. A piecewise-constant model estimated VE and waning VE from prior studies. All estimates were then combined in a cohort model to assess the vaccine preventable IPD burden of delivering 13-, 15-, 20-valent conjugate or 23-valent polysaccharide vaccines at various ages. In Brazil, Malawi, South Africa and England 51%, 51%, 54% and 39% of adults older than 55y were younger than 65y old. A smaller share of IPD was reported among adults y old in England (4,657 annual cases 20% y) compared to Brazil (186 45%), Malawi (4 63%), or South Africa (134, 48%). PCV13- and PPV23-serotypes were estimated to cause 39% and 85% of IPD cases on average across settings. Vaccination at 55y in Brazil, Malawi, and South Africa, and at 70y in England had the greatest potential for IPD prevention with 38%, 31%, 27%, 8% of IPD preventable if using PCV13, 44%, 32%, 30%, 13% with PCV15, 65%, 69%, 53%, 37% with PCV20, and 30%, 29%, 20%, 14% with PPV23, respectively. Vaccination efficiency or cost effective use was optimal in 60-65y in Brazil, Malawi and South Africa, and in 80-85y in England. In low/middle-income countries, pneumococcal vaccines may prevent a substantial proportion of the residual IPD burden if administered earlier in adulthood than is typical in high-income countries. UK National Institute for Health and Care Research. A recent review conducted for the World Health Organisation (WHO) Scientific Advisory Group of Experts (SAGE) working group on pneumococcal vaccines reviewed the evidence on the efficacy, effectiveness and potential impact of pneumococcal vaccines in older adults. At the time, little evidence was identified to support recommendations for the age of pneumococcal vaccination in older adults, particularly in LMICs. We did an updated search of PubMed, Medline, Embase and Web of Science for studies on age targeting for pneumococcal vaccination in older adults published from Jan 1, 2003 to June 30, 2022, using the search terms “(optimal age targeting OR age targeting OR timeliness) AND (pneumococcal vaccination OR pneumococcal vaccines) AND (adults OR older adults OR elderly)”. We identified one study on the role of timeliness in the cost-effectiveness of older adult vaccination in Australia. This study explored the impact of the timeliness of pneumococcal conjugate vaccination (PCV) in older adults and found that more hospitalisations and deaths can be prevented if PCV13 was given to 70y old than as recommended at 65y. On the other hand, most low-income countries (LICs) and middle-income countries (MICs) do not have routine older adult pneumococcal vaccination programmes, despite often less indirect protection from childhood PCV programmes and high burden of vaccine preventable disease. The implications of differences in population demographics and risk for IPD compared to high income countries on the optimal age for pneumococcal vaccination in LICs/MICs are unknown. This multicountry study uses data from long-standing older adult pneumococcal surveillance programmes at the national/sub-national level, to explore the optimal age-targeting for a single-dose pneumococcal vaccination against vaccine-serotype-IPD in older adults living without human immunodeficiency virus in LIC (Malawi), MICs (Brazil, South Africa), and HIC (England). We show that despite mature pneumococcal infant vaccination programmes there is a substantial burden of vaccine preventable pneumococcal disease remaining in the four countries considered. Vaccinating at 55y in the LICs/MICs was optimal whereas vaccinating at 70y prevented most IPD cases in England than vaccinating at other ages. While the number of older adults needed to vaccinate to prevent an IPD case may be higher for programmes vaccinating older in iduals, vaccination efficiency or vaccine cost effective use was optimal in 60-65y in LICs/MICs, and in 80-85y in England. LICs/MICs with a mature infant immunisation programme for pneumococci and a remaining high burden of vaccine preventable pneumococcal disease in older adults may consider implementation of a vaccination programme for older adults, albeit at a younger age than typical in HICs. Affordability and cost-effectiveness of an adult vaccination programme as well as the indirect effects following potential changes to higher valency infant PCV vaccination programmes will also need to be considered.
Publisher: Elsevier BV
Date: 08-2023
Publisher: MDPI AG
Date: 04-2021
DOI: 10.3390/MICROORGANISMS9040738
Abstract: Pneumococcal conjugate vaccine (PCV) introduction has reduced pneumococcal meningitis incidence. The Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) project described the serotype distribution of remaining pneumococcal meningitis in countries using PCV10/13 for least 5–7 years with primary series uptake above 70%. The distribution was estimated using a multinomial Dirichlet regression model, stratified by PCV product and age. In PCV10-using sites (N = 8 cases = 1141), PCV10 types caused 5% of cases years of age and 15% among ≥5 years the top serotypes were 19A, 6C, and 3, together causing 42% of cases years and 37% ≥5 years. In PCV13-using sites (N = 32 cases = 4503), PCV13 types caused 14% in and 26% in ≥5 years 4% and 13%, respectively, were serotype 3. Among the top serotypes are five (15BC, 8, 12F, 10A, and 22F) included in higher-valency PCVs under evaluation. Other top serotypes (24F, 23B, and 23A) are not in any known investigational product. In countries with mature vaccination programs, the proportion of pneumococcal meningitis caused by vaccine-in-use serotypes is lower (≤26% across all ages) than pre-PCV (≥70% in children). Higher-valency PCVs under evaluation target over half of remaining pneumococcal meningitis cases, but questions remain regarding generalizability to the African meningitis belt where additional data are needed.
Publisher: Microbiology Society
Date: 11-2019
Publisher: American Society for Microbiology
Date: 21-09-2017
Abstract: Shiga toxin-producing Escherichia coli (STEC) strains are primarily foodborne pathogens that may cause diarrheal outbreaks and are associated with severe complications, specifically hemolytic-uremic syndrome (HUS). We report here genome sequence data for STEC O26:H11, which is associated with a cluster of cases of HUS, a rarely described syndrome in South Africa.
No related grants have been discovered for Jackie Kleynhans.