Recurrent Potent Human Neutralizing Antibodies to Zika Virus in Brazil and Mexico.

Antibodies to Zika virus (ZIKV) can be protective. To examine the antibody response in individuals who develop high titers of anti-ZIKV antibodies, we screened cohorts in Brazil and Mexico for ZIKV envelope domain III (ZEDIII) binding and neutralization. We find that serologic reactivity to dengue 1 virus (DENV1) EDIII before ZIKV exposure is associated with increased ZIKV neutralizing titers after exposure. Antibody cloning shows that donors with high ZIKV neutralizing antibody titers have expanded clones of memory B cells that express the same immunoglobulin VH3-23/VK1-5 genes. These recurring antibodies cross-react with DENV1, but not other flaviviruses, neutralize both DENV1 and ZIKV, and protect mice against ZIKV challenge. Structural analyses reveal the mechanism of recognition of the ZEDIII lateral ridge by VH3-23/VK1-5 antibodies. Serologic testing shows that antibodies to this region correlate with serum neutralizing activity to ZIKV. Thus, high neutralizing responses to ZIKV are associated with pre-existing reactivity to DENV1 in humans.

Estimated population-level impact of pneumococcal conjugate vaccines against all-cause pneumonia mortality among unvaccinated age groups in five Latin American countries.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) provide strong direct protection in children, while limited data are available on their indirect effect on mortality among older age groups. This multi-country study aimed to assess the population-level impact of pediatric PCVs on all-cause pneumonia mortality among ≥5 years of age, and invasive pneumococcal disease (IPD) cases in Chile. METHODS: Demographic and mortality data from Argentina, Brazil, Chile, Colombia, and Mexico were collected considering the ≥ 5-year-old population, from 2000-2019, with 1,795,789 deaths due to all-cause pneumonia. IPD cases in Chile were also evaluated. Time series models were employed to evaluate changes in all-cause pneumonia deaths during the post-vaccination period, with other causes of death used as synthetic controls for unrelated temporal trends. RESULTS: No significant change in death rates due to all-cause pneumonia was detected following PCV introduction among most age groups and countries. The proportion of IPD cases caused by vaccine serotypes decreased from 29% (2012) to 6% (2022) among ≥65 years in Chile. DISCUSSION: While an effect of PCV against pneumonia deaths (a broad clinical definition that may not be specific enough to measure indirect effects) was not detected, evidence of indirect PCV impact was observed among vaccine-type-specific IPD cases.

Incorporating Efficacy Data from Initial Trials Into Subsequent Evaluations: Application to Vaccines Against Respiratory Syncytial Virus.

BACKGROUND: When a randomized controlled trial fails to demonstrate statistically significant efficacy against the primary endpoint, a potentially costly new trial would need to be conducted to receive licensure. Incorporating data from previous trials might allow for more efficient follow-up trials to demonstrate efficacy, speeding the availability of effective vaccines. METHODS: Based on the outcomes from a failed trial of a maternal vaccine against respiratory syncytial virus (RSV), we simulated data for a new Bayesian group-sequential trial. We analyzed the data either ignoring data from the previous trial (i.e., weakly informative prior distributions) or using prior distributions incorporating the historical data into the analysis. We evaluated scenarios where efficacy in the new trial was the same, greater than, or less than that in the original trial. For each scenario, we evaluated the statistical power and type I error rate for estimating the vaccine effect following interim analyses. RESULTS: When we used a stringent threshold to control the type I error rate, analyses incorporating historical data had a small advantage over trials that did not. If control of type I error is less important (e.g., in a postlicensure evaluation), the incorporation of historical data can provide a substantial boost in efficiency. CONCLUSIONS: Due to the need to control the type I error rate in trials used to license a vaccine, incorporating historical data provides little additional benefit in terms of stopping the trial early. However, these statistical approaches could be promising in evaluations that use real-world evidence following licensure.

Hypertension Control During the Coronavirus Disease 2019 Pandemic: A Cohort Study Among US Veterans.

DESIGN: Retrospective cohort study. OBJECTIVE: We sought to examine whether disruptions in follow-up intervals contributed to hypertension control. BACKGROUND: Disruptions in health care were widespread during the coronavirus disease 2019 pandemic. PATIENTS AND METHODS: We identified a cohort of individuals with hypertension in both prepandemic (March 2019-February 2020) and pandemic periods (March 2020-February 2022) in the Veterans Health Administration. First, we calculated follow-up intervals between the last prepandemic and first pandemic blood pressure measurement during a primary care clinic visit, and between measurements in the prepandemic period. Next, we estimated the association between the maintenance of (or achieving) hypertension control and the period using generalized estimating equations. We assessed associations between follow-up interval and control separately for periods. Finally, we evaluated the interaction between period and follow-up length. RESULTS: A total of 1,648,424 individuals met the study inclusion criteria. Among individuals with controlled hypertension, the likelihood of maintaining control was lower during the pandemic versus the prepandemic (relative risk: 0.93; 95% CI: 0.93, 0.93). Longer follow-up intervals were associated with a decreasing likelihood of maintaining controlled hypertension in both periods. Accounting for follow-up intervals, the likelihood of maintaining control was 2% lower during the pandemic versus the prepandemic. For uncontrolled hypertension, the likelihood of gaining control was modestly higher during the pandemic versus the prepandemic (relative risk: 1.01; 95% CI: 1.01, 1.01). The likelihood of gaining control decreased with follow-up length during the prepandemic but not pandemic. CONCLUSIONS: During the pandemic, longer follow-up between measurements contributed to the lower likelihood of maintaining control. Those with uncontrolled hypertension were modestly more likely to gain control in the pandemic.

Global patterns of rebound to normal RSV dynamics following COVID-19 suppression.

BACKGROUND: Annual epidemics of respiratory syncytial virus (RSV) had consistent timing and intensity between seasons prior to the SARS-CoV-2 pandemic (COVID-19). However, starting in April 2020, RSV seasonal activity declined due to COVID-19 non-pharmaceutical interventions (NPIs) before re-emerging after relaxation of NPIs. We described the unusual patterns of RSV epidemics that occurred in multiple subsequent waves following COVID-19 in different countries and explored factors associated with these patterns. METHODS: Weekly cases of RSV from twenty-eight countries were obtained from the World Health Organisation and combined with data on country-level characteristics and the stringency of the COVID-19 response. Dynamic time warping and regression were used to cluster time series patterns and describe epidemic characteristics before and after COVID-19 pandemic, and identify related factors. RESULTS: While the first wave of RSV epidemics following pandemic suppression exhibited unusual patterns, the second and third waves more closely resembled typical RSV patterns in many countries. Post-pandemic RSV patterns differed in their intensity and/or timing, with several broad patterns across the countries. The onset and peak timings of the first and second waves of RSV epidemics following COVID-19 suppression were earlier in the Southern than Northern Hemisphere. The second wave of RSV epidemics was also earlier with higher population density, and delayed if the intensity of the first wave was higher. More stringent NPIs were associated with lower RSV growth rate and intensity and a shorter gap between the first and second waves. CONCLUSION: Patterns of RSV activity have largely returned to normal following successive waves in the post-pandemic era. Onset and peak timings of future epidemics following disruption of normal RSV dynamics need close monitoring to inform the delivery of preventive and control measures.

Mapping partner drug resistance to guide antimalarial combination therapy policies in sub-Saharan Africa.

Resistance to artemisinin-based combination therapies (ACTs) threatens the global control of Plasmodium falciparum malaria. ACTs combine artemisinin-derived compounds with partner drugs to enable multiple mechanisms of clearance. Although ACTs remain widely effective in sub-Saharan Africa, long-standing circulation of parasite alleles associated with reduced partner drug susceptibility may contribute to the development of clinical resistance. We fitted a hierarchical Bayesian spatial model to data from over 500 molecular surveys to predict the prevalence and frequency of four key markers in transporter genes (pfcrt 76T and pfmdr1 86Y, 184F, and 1246Y) in first-level administrative divisions in sub-Saharan Africa from the uptake of ACTs (2004 to 2009) to their widespread usage (2010 to 2018). Our models estimated that the pfcrt 76T mutation decreased in prevalence in 90% of regions; the pfmdr1 N86 and D1246 wild-type genotypes increased in prevalence in 96% and 82% of regions, respectively; and there was no significant directional selection at the pfmdr1 Y184F locus. Rainfall seasonality was the strongest predictor of the prevalence of wild-type genotypes, with other covariates, including first-line drug policy and transmission intensity more weakly associated. We lastly identified regions of high priority for enhanced surveillance that could signify decreased susceptibility to the local first-line ACT. Our results can be used to infer the degree of molecular resistance and magnitude of wild-type reversion in regions without survey data to inform therapeutic policy decisions.

Potential Impact of Higher-Valency Pneumococcal Conjugate Vaccines Among Adults in Different Localities in Germany.

Next-generation pneumococcal conjugate vaccines (PCVs) have been approved for use. The serotype distribution of pneumococcal isolates can vary between regions. To understand the potential impacts of new PCVs, we evaluated trends in invasive pneumococcal disease (IPD) among adults in Germany at a local level using Bayesian hierarchical logistic regression. There was little spatial variation in IPD cases caused by PCV13 serotypes, which dropped from 60% of IPD cases in 2006 to 30% in 2018. Over half of IPD cases in 2018 were attributable to serotypes covered by new PCVs (PCV15, PCV20), which suggests they could further reduce the burden of IPD.

Year-Round Respiratory Syncytial Virus Transmission in The Netherlands Following the COVID-19 Pandemic: A Prospective Nationwide Observational and Modeling Study.

We initiated a nationwide prospective study to monitor respiratory syncytial virus (RSV)-related pediatric hospitalizations in 46 hospitals throughout the Netherlands between May 2021 and August 2022. We showed year-round RSV transmission in the Netherlands after an initial 2021 summer outbreak. The pattern was unprecedented and distinct from neighboring countries. We extended a dynamic simulation model to evaluate the impact of waning immunity on pediatric RSV hospitalizations in the Netherlands using 4 different scenarios. Our results suggest that the observed continuous RSV transmission pattern could be associated with waning immunity due to the period of very low RSV circulation during the COVID-19 pandemic.

Waning Effectiveness of the BNT162b2 Vaccine Against Infection in Adolescents in Israel.

BACKGROUND: The short-term effectiveness of a 2-dose regimen of the BioNTech/Pfizer BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, however, that waning of vaccine-induced immunity against infection in adult populations is evident within a few months. METHODS: Leveraging the database of Maccabi Healthcare Services (MHS), we conducted a matched case-control design for evaluating the association between time since vaccination and the incidence of infections, where 2 outcomes were evaluated: documented SARS-CoV-2 infection (regardless of symptoms) and symptomatic infection (COVID-19). Cases were defined as individuals aged 12-16 with a positive polymerase chain reaction (PCR) test occurring between 15 June and 8 December 2021, when the Delta variant was dominant in Israel. Controls were adolescents who had not tested positive previously. RESULTS: We estimated a peak vaccine effectiveness between 2 weeks and 3 months following receipt of the second dose, with 85% (95% confidence interval [CI]: 84-86%) and 90% (95% CI: 89-91%) effectiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19), respectively. However, in line with findings for adults, waning effectiveness was evident. Long-term protection was reduced to 73% (95% CI: 68-77%) against infection and 79% (95% CI: 73-83%) against COVID-19 3-5 months after the second dose and waned to 53% (95% CI: 46-60%) against infection and 66% (95% CI: 59-72%) against COVID-19 after 5 months. CONCLUSIONS: Although vaccine-induced protection against both infection and COVID-19 continues over time in adolescents, the protection wanes with time since vaccination, starting 3 months after inoculation and continuing for more than 5 months.

Reconstructing the course of the COVID-19 epidemic over 2020 for US states and counties: Results of a Bayesian evidence synthesis model.

Reported COVID-19 cases and deaths provide a delayed and incomplete picture of SARS-CoV-2 infections in the United States (US). Accurate estimates of both the timing and magnitude of infections are needed to characterize viral transmission dynamics and better understand COVID-19 disease burden. We estimated time trends in SARS-CoV-2 transmission and other COVID-19 outcomes for every county in the US, from the first reported COVID-19 case in January 13, 2020 through January 1, 2021. To do so we employed a Bayesian modeling approach that explicitly accounts for reporting delays and variation in case ascertainment, and generates daily estimates of incident SARS-CoV-2 infections on the basis of reported COVID-19 cases and deaths. The model is freely available as the covidestim R package. Nationally, we estimated there had been 49 million symptomatic COVID-19 cases and 404,214 COVID-19 deaths by the end of 2020, and that 28% of the US population had been infected. There was county-level variability in the timing and magnitude of incidence, with local epidemiological trends differing substantially from state or regional averages, leading to large differences in the estimated proportion of the population infected by the end of 2020. Our estimates of true COVID-19 related deaths are consistent with independent estimates of excess mortality, and our estimated trends in cumulative incidence of SARS-CoV-2 infection are consistent with trends in seroprevalence estimates from available antibody testing studies. Reconstructing the underlying incidence of SARS-CoV-2 infections across US counties allows for a more granular understanding of disease trends and the potential impact of epidemiological drivers.

Reemergence of Invasive Pneumococcal Disease in Germany During the Spring and Summer of 2021.

BACKGROUND: The incidence of invasive pneumococcal disease (IPD) decreased worldwide in 2020 and the first quarter of 2021, concurrent with nonpharmaceutical interventions (NPIs) intended to stymie transmission of SARS-CoV-2. In 2021, the stringency of these NPI strategies has varied. We investigated age- and serotype-specific variations in IPD case counts in Germany in 2020-2021. METHODS: IPD cases through 30 November 2021 were stratified by age group, serotype, or geographic location. IPD surveillance data in 2020-2021 were compared with (1) IPD surveillance data from 2015-2019, (2) mobility data during 2020 and 2021, and (3) NPI stringency data in 2020 and 2021. RESULTS: IPD incidence began to return toward baseline among children 0-4 years old in April 2021 and exceeded baseline by June 2021 (a 9% increase over the average monthly values for 2015-2019). Children aged 5-14 years and adults aged 15-34 or ≥80 years showed increases in IPD cases that exceeded baseline values starting in July 2021, with increases also starting in spring 2021. The age distribution and proportion of vaccine-serotype IPD remained comparable to those in previous years, despite lower overall case counts in 2020 and 2021. The percentage change in IPD incidence compared with the previous 5 years was correlated with changes in mobility and with NPI stringency. CONCLUSIONS: IPD levels began to return to and exceed seasonal levels in spring and summer 2021 in Germany, following sharp declines in 2020 that coincided with NPIs related to the coronavirus disease 2019 pandemic. Proportions of vaccine serotypes remained largely consistent throughout 2020-2021.

Decline in Pneumococcal Disease in Young Children During the Coronavirus Disease 2019 (COVID-19) Pandemic in Israel Associated With Suppression of Seasonal Respiratory Viruses, Despite Persistent Pneumococcal Carriage: A Prospective Cohort Study.

BACKGROUND: The incidence of invasive pneumococcal disease (IPD) declined during the COVID-19 pandemic. Previous studies hypothesized that this was due to reduced pneumococcal transmission resulting from nonpharmaceutical interventions. We used multiple ongoing cohort surveillance projects in children <5 years to test this hypothesis. METHODS: The first SARS-CoV-2 cases were detected in February 2020, resulting in a full lockdown, followed by several partial restrictions. Data from ongoing surveillance projects captured the incidence dynamics of community-acquired alveolar pneumonia (CAAP), nonalveolar lower respiratory infections necessitating chest X-rays (NA-LRIs), nasopharyngeal pneumococcal carriage in nonrespiratory visits, nasopharyngeal respiratory virus detection (by polymerase chain reaction), and nationwide IPD. Monthly rates (January 2020 through February 2021 vs mean monthly rates 2016-2019 [expected rates]) adjusted for age and ethnicity were compared. RESULTS: CAAP and bacteremic pneumococcal pneumonia were strongly reduced (incidence rate ratios [IRRs]: .07 and .19, respectively); NA-LRIs and nonpneumonia IPD were also reduced by a lesser magnitude (IRRs: .46 and .42, respectively). In contrast, pneumococcal carriage prevalence was only slightly reduced, and density of colonization and pneumococcal serotype distributions were similar to previous years. The decline in pneumococcus-associated disease was temporally associated with a full suppression of respiratory syncytial virus, influenza viruses, and human metapneumovirus, often implicated as co-pathogens with pneumococcus. In contrast, adenovirus, rhinovirus, and parainfluenza activities were within or above expected levels. CONCLUSIONS: Reductions in pneumococcal and pneumococcus-associated diseases occurring during the COVID-19 pandemic in Israel were not predominantly related to reduced pneumococcal carriage and density but were strongly associated with the disappearance of specific respiratory viruses.

Evaluating the Impact of Meningococcal Vaccines With Synthetic Controls.

Invasive meningococcal disease (IMD) has a low and unpredictable incidence, presenting challenges for real-world evaluations of meningococcal vaccines. Traditionally, meningococcal vaccine impact is evaluated by predicting counterfactuals from pre-immunization IMD incidences, possibly controlling for IMD in unvaccinated age groups, but the selection of controls can influence results. We retrospectively applied a synthetic control (SC) method, previously used for pneumococcal disease, to data from 2 programs for immunization of infants against serogroups B and C IMD in England and Brazil. Time series of infectious/noninfectious diseases in infants and IMD cases in older unvaccinated age groups were used as candidate controls, automatically combined in a SC through Bayesian variable selection. SC closely predicted IMD in absence of vaccination, adjusting for nontrivial changes in IMD incidence. Vaccine impact estimates were in line with previous assessments. IMD cases in unvaccinated age groups were the most frequent SC-selected controls. Similar results were obtained when excluding IMD from control sets and using other diseases only, particularly respiratory diseases and measles. Using non-IMD controls may be important where there are herd immunity effects. SC is a robust and flexible method that addresses uncertainty introduced when equally plausible controls exhibit different post-immunization behaviors, allowing objective comparisons of IMD programs between countries.

Serotype Patterns of Pneumococcal Disease in Adults Are Correlated With Carriage Patterns in Older Children.

BACKGROUND: The importance of specific serotypes causing invasive pneumococcal disease (IPD) differs by age. Data on pneumococcal carriage in different age groups, along with data on serotype-specific invasiveness, could help explain these age-related patterns and their implications for vaccination. METHODS: Using pneumococcal carriage and disease data from Israel, we evaluated the association between serotype-specific IPD in adults and serotype-specific carriage prevalence among children in different age categories, while adjusting for serotype-specific invasiveness. We estimated carriage prevalence using different age groupings that were selected a priori. The Deviance Information Criterion was used to determine which age groupings of carriage data best fit the adult IPD data. Serotype-specific disease patterns were further evaluated by stratifying IPD data by comorbidity status. RESULTS: The relative frequency of serotypes causing IPD differed between adults and children, and also differed between older and younger adults and between adults with and without comorbidities. Serotypes overrepresented as causes of IPD in adults were more commonly carried in older children compared with younger children. In line with this, the serotype-specific frequency of carriage in older children, rather than infants, best correlated with serotype-specific IPD in adults. CONCLUSIONS: These analyses demonstrate that the serotype patterns in carriage in older children, rather than infants, are best correlated with disease patterns in adults. This might suggest these older children are more influential for disease patterns in adults. These insights could help in optimizing vaccination strategies to reduce disease burden across all ages.

Excess Cerebrovascular Mortality in the United States During the COVID-19 Pandemic.

BACKGROUND AND PURPOSE: The magnitude and drivers of excess cerebrovascular-specific mortality during the coronavirus disease 2019 (COVID-19) pandemic are unknown. We aim to quantify excess stroke-related deaths and characterize its association with social distancing behavior and COVID-19-related vascular pathology. METHODS: United States and state-level excess cerebrovascular deaths from January to May 2020 were quantified using National Center for Health Statistic data and Poisson regression models. Excess cerebrovascular deaths were analyzed as a function of time-varying stroke-related emergency medical service (EMS) calls and cumulative COVID-19 deaths using linear regression. A state-level regression analysis was performed to determine the association between excess cerebrovascular deaths and time spent in residences, measured by Google Community Mobility Reports, during the height of the pandemic after the first COVID-19 death (February 29). RESULTS: Forty states and New York City were included. Excess cerebrovascular mortality occurred nationally from the weeks ending March 28 to May 2, 2020, up to a 7.8% increase above expected levels during the week of April 18. Decreased stroke-related EMS calls were associated with excess stroke deaths one (70 deaths per 1000 fewer EMS calls [95% CI, 20-118]) and 2 weeks (85 deaths per 1000 fewer EMS calls [95% CI, 37-133]) later. Twenty-three states and New York City experienced excess cerebrovascular mortality during the pandemic height. A 10% increase in time spent at home was associated with a 4.3% increase in stroke deaths (incidence rate ratio, 1.043 [95% CI, 1.001-1.085]) after adjusting for COVID-19 deaths. CONCLUSIONS: Excess US cerebrovascular deaths during the COVID-19 pandemic were observed and associated with decreases in stroke-related EMS calls nationally and mobility at the state level. Public health measures are needed to identify and counter the reticence to seeking medical care for acute stroke during the COVID-19 pandemic.

Differences and Temporal Changes in Risk of Invasive Pneumococcal Disease in Adults with Hematological Malignancies: Results from a Nationwide 16-Year Cohort Study.

BACKGROUND: Patients with hematological malignancies (HM) are known to carry an increased risk of invasive pneumococcal disease (IPD). However, temporal variations in IPD risks following a cancer diagnosis remain poorly characterized. To inform vaccine guidelines and patient management, we assessed the IPD incidence among patients with HM and other malignancies. METHODS: The study population included all individuals aged ≥15 years during 2000-2016 in Denmark. Variations in incidences of IPD over time and between different types of hematological malignancies and diagnoses were assessed by Poisson regression. RESULTS: During 85 002 224 person-years of observation, 13 332 episodes of a first IPD were observed, of which 765 (5.7%) occurred among individuals with HM. Among HM patients, the IPD incidence rate decreased continuously during the study period (rate ratio per year, 0.91; 95% confidence interval, .90-.92). The risk of IPD in patients with HM was up to 39 times higher when compared to the background population and was highest for multiple myeloma, acute lymphoblastic leukemia, and chronic lymphocytic leukemia. Unlike other malignancies, the increased IPD risk did not wane with the time since HM diagnosis. We found a vaccination uptake of only ≤2% in patients with HM and ≤1% for those with other types of malignancies. CONCLUSIONS: Adults with HM in general and patients with lymphoid malignancies in particular have an increased risk for IPD, compared with patients with other types of cancer and with individuals free of cancer. The pneumococcal vaccination uptake is extremely low in this at risk-population. Efforts to prevent IPD in HM patients are continuously warranted.

Declines in Pneumonia Mortality Following the Introduction of Pneumococcal Conjugate Vaccines in Latin American and Caribbean Countries.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) are recommended for use in pediatric immunization programs worldwide. Few data are available on their effect against mortality. We present a multicountry evaluation of the population-level impact of PCVs against death due to pneumonia in children < 5 years of age. METHODS: We obtained national-level mortality data between 2000 and 2016 from 10 Latin American and Caribbean countries, using the standardized protocol. Time series models were used to evaluate the decline in all-cause pneumonia deaths during the postvaccination period while controlling for unrelated temporal trends using control causes of death. RESULTS: The estimated declines in pneumonia mortality following the introduction of PCVs ranged from 11% to 35% among children aged 2-59 months in 5 countries: Colombia (24% [95% credible interval {CrI}, 3%-35%]), Ecuador (25% [95% CrI, 4%-41%]), Mexico (11% [95% CrI, 3%-18%]), Nicaragua (19% [95% CrI, 0-34%]), and Peru (35% [95% CrI, 20%-47%]). In Argentina, Brazil, and the Dominican Republic, the declines were not detected in the aggregated age group but were detected in certain age strata. In Guyana and Honduras, the estimates had large uncertainty, and no declines were detected. Across the 10 countries, most of which have low to moderate incidence of pneumonia mortality, PCVs have prevented nearly 4500 all-cause pneumonia deaths in children 2-59 months since introduction. CONCLUSIONS: Although the data quality was variable between countries, and the patterns varied across countries and age groups, the balance of evidence suggests that mortality due to all-cause pneumonia in children declined after PCV introduction. The impact could be greater in populations with a higher prevaccine burden of pneumonia.

SARS-CoV-2 in Nursing Homes after 3 Months of Serial, Facilitywide Point Prevalence Testing, Connecticut, USA.

Nursing homes house populations that are highly vulnerable to coronavirus disease. Point prevalence surveys (PPSs) provide information on the severe acute respiratory syndrome coronavirus 2 infection status of staff and residents in nursing homes and enable isolation of infectious persons to halt disease spread. We collected 16 weeks of public health surveillance data on a subset of nursing homes (34/212) in Connecticut, USA. We fit a Poisson regression model to evaluate the association between incidence and time since serial PPS onset, adjusting for decreasing community incidence and other factors. Nursing homes conducted a combined total of 205 PPSs in staff and 232 PPSs in residents. PPS was associated with 41%-80% reduction in incidence rate in nursing homes. Our findings provide support for the use of repeated PPSs in nursing home staff and residents, combined with strong infection prevention measures such as cohorting, in contributing to outbreak control.

Increased SARS-CoV-2 Testing Capacity with Pooled Saliva Samples.

We analyzed feasibility of pooling saliva samples for severe acute respiratory syndrome coronavirus 2 testing and found that sensitivity decreased according to pool size: 5 samples/pool, 7.4% reduction; 10 samples/pool, 11.1%; and 20 samples/pool, 14.8%. When virus prevalence is >2.6%, pools of 5 require fewer tests; when <0.6%, pools of 20 support screening strategies.

Estimated impact of the pneumococcal conjugate vaccine on pneumonia mortality in South Africa, 1999 through 2016: An ecological modelling study.

BACKGROUND: Data on the national-level impact of pneumococcal conjugate vaccine (PCV) introduction on mortality are lacking from Africa. PCV was introduced in South Africa in 2009. We estimated the impact of PCV introduction on all-cause pneumonia mortality in South Africa, while controlling for changes in mortality due to other interventions. METHODS AND FINDINGS: We used national death registration data in South Africa from 1999 to 2016 to assess the impact of PCV introduction on all-cause pneumonia mortality in all ages, with the exclusion of infants aged <1 month. We created a composite (synthetic) control using Bayesian variable selection of nondiarrheal, nonpneumonia, and nonpneumococcal deaths to estimate the number of expected all-cause pneumonia deaths in the absence of PCV introduction post 2009. We compared all-cause pneumonia deaths from the death registry to the expected deaths in 2012 to 2016. We also estimated the number of prevented deaths during 2009 to 2016. Of the 9,324,638 deaths reported in South Africa from 1999 to 2016, 12·6% were pneumonia-related. Compared to number of deaths expected, we estimated a 33% (95% credible interval (CrI) 26% to 43%), 23% (95%CrI 17% to 29%), 25% (95%CrI 19% to 32%), and 23% (95%CrI 11% to 32%) reduction in pneumonia mortality in children aged 1 to 11 months, 1 to 4 years, 5 to 7 years, and 8 to 18 years in 2012 to 2016, respectively. In total, an estimated 18,422 (95%CrI 12,388 to 26,978) pneumonia-related deaths were prevented from 2009 to 2016 in children aged <19 years. No declines were estimated observed among adults following PCV introduction. This study was mainly limited by coding errors in original data that could have led to a lower impact estimate, and unmeasured factors could also have confounded estimates. CONCLUSIONS: This study found that the introduction of PCV was associated with substantial reduction in all-cause pneumonia deaths in children aged 1 month to <19 years. The model predicted an effect of PCV in age groups who were eligible for vaccination (1 months to 4 years), and an indirect effect in those too old (8 to 18 years) to be vaccinated. These findings support sustaining pneumococcal vaccination to reduce pneumonia-related mortality in children.