Determinants of high residual post-PCV13 pneumococcal vaccine-type carriage in Blantyre, Malawi:a modelling study

Background In November 2011, Malawi introduced the 13-valent pneumococcal conjugate vaccine (PCV13) into the routine infant schedule. Four to 7 years after introduction (2015–2018), rolling prospective nasopharyngeal carriage surveys were performed in the city of Blantyre. Carriage of Streptococcus pneumoniae vaccine serotypes (VT) remained higher than reported in high-income countries, and impact was asymmetric across age groups. Methods A dynamic transmission model was fit to survey data using a Bayesian Markov-chain Monte Carlo approach, to obtain insights into the determinants of post-PCV13 age-specific VT carriage. Results Accumulation of naturally acquired immunity with age and age-specific transmission potential were both key to reproducing the observed data. VT carriage reduction peaked sequentially over time, earlier in younger and later in older age groups. Estimated vaccine efficacy (protection against carriage) was 66.87% (95% CI 50.49–82.26%), similar to previous estimates. Ten-year projected vaccine impact (VT carriage reduction) among 0–9 years old was lower than observed in other settings, at 76.23% (CI 95% 68.02–81.96%), with sensitivity analyses demonstrating this to be mainly driven by a high local force of infection. Conclusions There are both vaccine-related and host-related determinants of post-PCV13 pneumococcal VT transmission in Blantyre with vaccine impact determined by an age-specific, local force of infection. These findings are likely to be generalisable to other Sub-Saharan African countries in which PCV impact on carriage (and therefore herd protection) has been lower than desired, and have implications for the interpretation of post-PCV carriage studies and future vaccination programs.</p

Pairwise scale space comparison of time series with application to climate research

In this paper, we study how sea surface temperature variations in the North Atlantic and the Norwegian Sea are correlated with the climate in the Northern Hemisphere in late Holocene. The analysis is performed by testing statistical hypotheses through novel scale space methodologies. In late Holocene, the proposed techniques reveal that the climate development in the subpolar North Atlantic has been incoherent with the development in the Norwegian Sea and the Northern Hemisphere. A prominent discrepancy between the three analyzed series is identified for the periods associated with the Medieval Warm Period and the Little Ice Age. A divergence between the oceanic series and the global Northern Hemisphere temperature estimate detected in the twentieth century is in line with the inferred imprint of recent climate change which suggests accentuated warming, in particular over continental regions. Overall, the results obtained by scale space analysis underscore the significance of the northern North Atlantic in shaping the climate globally, mainly through changes in the strength and structure of the Atlantic meridional overturning circulation

Comparative analysis of Streptococcus pneumoniae transmission in Portuguese and Finnish day-care centres

Day-care centre (DCC) attendees play a central role in maintaining the circulation of Streptococcus pneumoniae (pneumococcus) in the population. The prevalence of pneumococcal carriage is highest in DCC attendees but varies across countries and is found to be consistently lower in Finland than in Portugal. We compared key parameters underlying pneumococcal transmission in DCCs to understand which of these contributed to the observed differences in carriage prevalence.PneumoCarr Consortium, Bill and Melinda Gates Foundation grant