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We present a novel method for coastal tsunami prediction utilizing a denoising autoencoder (DAE) model, one of the deep learning algorithms. Our study focuses on the Tohoku coast, Japan, where dense offshore bottom pressure gauges (OBPGs), called S-net, are installed. To train the model, we generated 800 hypothetical tsunami scenarios by employing stochastic earthquake models (M7.0–8.8). We used synthetic tsunami waveforms at 44 OBPGs as input and the waveforms at four coastal tide gauges as output. Subsequently, we evaluated the model's performance using 200 additional hypothetical and two real tsunami events: the 2016 Fukushima earthquake and 2022 Tonga volcanic tsunamis. Our DAE model demonstrated high accuracy in predicting coastal tsunami waveforms for hypothetical events, achieving an impressive quality index of approximately 90%. Furthermore, it accurately forecasted the maximum amplitude of the 2016 Fukushima tsunami, achieving a quality index of 91.4% at 15 min after the earthquake. However, the prediction of coastal waveforms for the 2022 Tonga volcanic tsunami was not satisfactory. We also assessed the impact of the forecast time window and found that it had limited effects on forecast accuracy. This suggests that our method is suitable for providing rapid forecasts soon after an earthquake occurs. Our research is the first application of an artificial neural network to tsunami prediction using real observations. In the future, we will use more tsunami scenarios for model training to enhance its robustness for different types of tsunamis. [ABSTRACT FROM AUTHOR]

High‐frequency (HF) radar monitors the sea surface current velocity and provides information for tsunami early warning. SeaSondeR, an HF ocean radar system in the eastern Tsugaru Strait, Japan, measured the tsunami‐induced current velocity during the 2022 Tonga volcanic tsunami. As an air‐coupled tsunami, the generating mechanism was complex, making it difficult to predict coastal tsunamis using traditional early warning methods. We adopted the tsunami data assimilation (DA) approach, which reconstructs the tsunami wavefield using offshore data and does not require source information, to forecast the coastal tsunami waveforms. Observations from the HF radar and offshore bottom pressure gauges (OBPGs) were used as the input for tsunami DA. The assimilation process started at 09:00 (UTC, hereafter) and forecasts were made at 14:00 and 15:00. The surface current velocity recorded by the HF radar reached the maximum (∼0.25 m/s) at 13:00, which corresponded to a negative phase of ∼2 cm sea level variation observed by OBPGs. We compared the forecasted waveforms with the observed waveforms at Hakodate and Shimokita tide gauges. The assimilation results obtained using HF radar showed a better performance in tsunami forecasting than those using OBPG in this case study. At 14:00, the forecasting accuracy indices were 91% and 67% for the next 2 and 6 hr, respectively. At 15:00, it was 63% and 70% for the next 2 and 6 hr, respectively. We suggest that HF radar could be a good supplement to OBPG for tsunami early warning purposes. Plain Language Summary: On 15 January 2022, the eruption of the Hunga Tonga–Hunga Ha'apai volcano generated a tsunami that arrived in Japan. The tsunami was detected by a high‐frequency (HF) ocean radar system in the eastern Tsugaru Strait. The HF radar recorded the velocity of tsunami‐induced sea surface currents. We used these velocity data to forecast the tsunami waveforms at coastal tide gauge stations. The forecast method, called tsunami data assimilation, does not require tsunami source information but accurately forecasts the coastal tsunami waveforms. We demonstrate that the HF radar data can be successfully applied to tsunami early warning systems. Key Points: High‐frequency (HF) radar observed surface current velocity in the eastern Tsugaru Strait during the 2022 Tonga volcanic tsunamiHF radar observations were used for data assimilation to forecast tsunami waveforms at coastal tide gaugesThe assimilation results using HF radar had an accuracy of over 63% for Hakodate and Shimokita tide gauges [ABSTRACT FROM AUTHOR]

We estimated the time difference between the 1854 CE Ansei–Tokai and Ansei–Nankai earthquakes from tidal records of two tide gauge stations (San Francisco and San Diego) on the west coast of North America. The first signals of the Ansei–Tokai tsunami were apparent, whereas those of the Ansei–Nankai tsunami were obscured by the later waves of the Ansei–Tokai tsunami. Waveforms of the Ansei–Nankai tsunami simulated with nonlinear dispersive wave theory by assuming an origin time of 07:00 GMT on 24 December arrived earlier than in the observations. The normalized root mean square and the misfit between the simulated and observed waveforms of the Ansei–Nankai tsunami showed a time difference between them of approximately 0.4 h. This finding suggests that the actual origin time of the Ansei–Nankai tsunami was approximately 07:24 GMT on 24 December. A previous study estimated the origin time of the Ansei–Tokai tsunami to be about 00:30 GMT on 23 December. Thus, we concluded that the time difference between the 1854 CE Ansei–Tokai and Ansei–Nankai tsunamis was 30.9 h. Despite the significant difference in the time resolution between the seasonal timekeeping system used in Japan in 1854 and waveform digitization, our result is roughly in agreement with historical descriptions of the tsunamis, suggesting that such information can be effectively used to determine the origin times of historical earthquakes. [ABSTRACT FROM AUTHOR]

Although tsunamis are dispersive water waves, hazard maps for earthquake-generated tsunamis neglect dispersive effects because the spatial dimensions of tsunamis are much greater than the water depth, and dispersive effects are generally small. Furthermore, calculations that include non-dispersive effects tend to predict higher tsunamis than ones that include dispersive effects. Although non-dispersive models may overestimate the tsunami height, this conservative approach is acceptable in disaster management, where the goal is to save lives and protect property. However, we demonstrate that offshore frequency dispersion amplifies tsunamis caused by outer-rise earthquakes, which displace the ocean bottom downward in a narrow area, generating a dispersive short-wavelength and pulling-dominant (water withdrawn) tsunami. We compared observational evidence and calculations of tsunami for a 1933 Mw 8.3 outer-rise earthquake along the Japan Trench. Dispersive (Boussinesq) calculations predicted significant frequency dispersion in the 1933 tsunami. The dispersive tsunami deformation offshore produced tsunami inundation heights that were about 10% larger than those predicted by non-dispersive (long-wave) calculations. The dispersive tsunami calculations simulated the observed tsunami inundation heights better than did the non-dispersive tsunami calculations. Contrary to conventional practice, we conclude that dispersive calculations are essential when preparing deterministic hazard maps for outer-rise tsunamis. [ABSTRACT FROM AUTHOR]

Background: The open-label, randomized, active-controlled KEYNOTE-045 study (NCT02256436) showed that second-line pembrolizumab significantly improved overall survival (OS) of patients with advanced/metastatic urothelial cancer (UC) that progressed after first-line platinum-containing chemotherapy, compared with standard chemotherapy (paclitaxel, docetaxel, or vinflunine). Pembrolizumab is approved for patients with bladder cancer in Japan. Patients and methods: Analysis was performed in the subgroup of Japanese patients enrolled in the KEYNOTE-045 study. Coprimary end points were OS and progression-free survival (PFS). Objective response rate (ORR) and safety were secondary end points. Results: Fifty-two Japanese patients (pembrolizumab, n = 30; chemotherapy, n = 22) were followed up for a median of 26.1 months. Patients who received pembrolizumab compared with chemotherapy had a 19% lower risk for death (hazard ratio [HR] 0.81, 95% CI 0.44–1.50); after adjusting for baseline covariates, the HR for OS was 0.61 (95% CI 0.32–1.15). The 24-month OS rate was higher with pembrolizumab (26.9% vs 14.3%). PFS was 2.0 and 4.9 months for pembrolizumab and chemotherapy, respectively (HR 1.71, 95% CI 0.95–3.08). ORR was similar for pembrolizumab and chemotherapy (20.0% vs 18.2%); durability of response was higher with pembrolizumab: 67% and 33% of patients, respectively, maintained a response for > 12 months. Treatment-related adverse events, including grade 3–5 events, occurred less frequently with pembrolizumab. Conclusions: Pembrolizumab provided durable antitumor activity in patients with locally advanced/metastatic UC that progressed after platinum-containing chemotherapy in the overall population and in the Japanese subgroup; safety profile was consistent with that previously observed for pembrolizumab. [ABSTRACT FROM AUTHOR]

Abstract Objective This study examined the prevalence of chronic comorbidities and the use of co-medications among people living with HIV (PLWH) on antiretrovirals in Japan, compared with age-matched controls without HIV. Methods This was an observational, retrospective, cross-sectional study using a hospital claims database of Japanese hospitals with advanced medical capabilities (i.e., advanced treatment hospitals, general hospitals, acute care hospitals). We extracted data for PLWH aged ≥18 years with a prescription record of antiretrovirals between January 2010 and December 2015, and for age-, sex-, and hospital-matched people without HIV. For each group, chronic comorbidities (diabetes, hypertension, lipid disorders, vascular diseases, chronic kidney failure, cancers, psychiatric disorders, osteoporosis, and hepatitis B/C co-infection), and co-medications were examined by age group. Results We analyzed data for 1445 PLWH and 14,450 people without HIV. The proportion of patients with multiple comorbidities was much greater among PLWH than controls of the same age group. Lipid disorders and diabetes were more prevalent in PLWH than controls (31.6% vs. 10.3% and 26.8% vs. 13.2%, respectively), both of which were more common in PLWH at earlier ages. Cancer was present in 8.1% of PLWH and 8.9% of controls. A greater proportion of PLWH used multiple co-medications other than antiretrovirals at earlier ages than controls. Conclusion PLWH taking antiretrovirals in Japan had a greater burden of comorbidities and co-medications with increasing age than people without HIV. In addition to appropriate management of comorbidities, medication reconciliation according to patients' co-medication profiles is important for successful management of this patient population. [ABSTRACT FROM AUTHOR]

A large amount of buildings was damaged or destroyed by the 2011 Great East Japan tsunami. Numerous field surveys were conducted in order to collect the tsunami inundation extents and building damage data in the affected areas. Therefore, this event provides us with one of the most complete data set among tsunami events in history. In this study, fragility functions are derived using data provided by the Ministry of Land, Infrastructure and Transportation of Japan, with more than 250,000 structures surveyed. The set of data has details on damage level, structural material, number of stories per building and location (town). This information is crucial to the understanding of the causes of building damage, as differences in structural characteristics and building location can be taken into account in the damage probability analysis. Using least squares regression, different sets of fragility curves are derived to demonstrate the influence of structural material, number of stories and coastal topography on building damage levels. The results show a better resistant performance of reinforced concrete and steel buildings over wood or masonry buildings. Also, buildings taller than two stories were confirmed to be much stronger than the buildings of one or two stories. The damage characteristic due to the coastal topography based on limited number of data in town locations is also shortly discussed here. At the same tsunami inundation depth, buildings along the Sanriku ria coast were much greater damaged than buildings from the plain coast in Sendai. The difference in damage states can be explained by the faster flow velocities in the ria coast at the same inundation depth. These findings are key to support better future building damage assessments, land use management and disaster planning. [ABSTRACT FROM AUTHOR]

On March 11th, 2011, the Pacific coast of Japan was hit by a tsunami generated by the largest earthquake (M9.0) in the history of the country and causing a wide range of devastating damage. Using preliminary reported data from many sources, some topics such as tsunami fatality ratio and tsunami fragility curves for structural damage are discussed and compared with other countries. This paper aims to discuss the damage characteristics of this tsunami as well as its mechanism, as observed through field surveys conducted over the 4 months following the tsunami. The field survey covers 13 areas in the Miyagi prefecture from Kesennuma city in the northernmost region to Yamamoto town in the southernmost region. The arrival time of the first tsunami along the coastal areas in the Miyagi prefecture was confirmed by stopped clocks found during the survey. The damage mechanism of coastal structures such as breakwaters, seawalls, tsunami gates, and evacuation buildings was investigated and discussed. Damage characteristics for each area, i.e., urban areas, port, coastal structures, fisheries, and agricultural areas, were also summarized. The conclusions drawn from the data analysis suggest that experience and education (soft countermeasures) are important to reduce the loss of life, as shown for example in the Sanriku area. The field surveys indicate that wood and reinforced-concrete (RC) structures should be balanced to survive both earthquake and tsunami forces, and the structural design for buildings should be reconsidered after the example in Onagawa town. In addition, coastal structures for tsunami countermeasures (hard countermeasures) should be more properly designed for survival instead of becoming floating debris upon being overturned by a tsunami. The combination of both hard and soft measures is especially necessary for optimizing the outcomes following a great disaster. These recommendations should be taken into consideration in the reconstruction efforts for better tsunami countermeasures in the future. [ABSTRACT FROM AUTHOR]

At 14:46 JST on March 11, 2011 a magnitude 9.0 earthquake (2011 Tohoku Earthquake and Tsunami) occurred off the Pacific Coast of Miyagi Prefecture. This study investigated the extensive changes in beach morphology due to the earthquake and tsunami along the 15 km Northern Sendai Coast using remotely sensed data. The remote sensing analysis on the beach topography and coastal forest demonstrated the following notable characteristics of beach morphological change: erosion of the northern barrier at the mouths of the Nanakitagawa and Natorigawa Rivers; erosion at an old river channel; scour landward of the seawalls in the longshore direction; erosion and deposition in beach areas with detached breakwaters; and deposition in coastal forest areas. Linkage of the deposition in the forest areas with the damage type of coastal forests was observed. The impact of the earthquake and tsunami on the beach morphology was serious; roughly 60% of the study area was degraded by 0.2-0.5 m in elevation mainly due to land subsidence, and a total of 0.4 km2 of beach area was eroded mainly due to erosion of the northern barrier at the mouths of the Nanakitagawa and Natorigawa Rivers. This study explores the geographical changes brought on by a tremendous earthquake and tsunami, which will help to elucidate the mechanisms of coastal forest destruction, beach erosion, and their interaction during tsunami events. [ABSTRACT FROM AUTHOR]

Japan was hit by the tsunami generated by the greatest earthquake in the history of Japan. The authors conducted the post-tsunami field survey in Miyagi prefecture immediately after the event to measure the inundation depth and investigate damaged buildings. Most of the buildings surveyed were wooden houses and could be classified into 4 damage levels. The primary data of inundation depth and damage levels obtained from the field survey were used to create the tsunami fragility curves, which described the degree of structural damage as a function of the hydrodynamic characteristics of tsunami inundation. The developed fragility curves show that damage with more than a 50% chance of occurring is classified as minor damage, moderate damage, major damage and complete damage when the tsunami inundation depth is between 2.5-3.0 m, 3.0-4.0 m and 4.0-4.5 m and greater than 4.5 m, respectively. By comparing the developed tsunami fragility curves, wooden houses in the studied area have higher structural performance than those obtained from historical events in other areas. The new curves suggest that wooden houses will be severely damaged if the inundation depth is greater than 3 m and collapse if the depth is greater than 4 m while wooden houses from historical data can resist only 1-2 m. Moreover, wooden walls in Japan reduce the overall failure of a structural member because a wooden wall is easier to destroy (compared to brick walls in Thailand and Indonesia) and allows the tsunami to pass through, which reduces the pressure at the attacking front of the tsunami. The fragility curves are very important for the loss estimation and reconstruction plans of the city; they are also crucial for reducing the disaster damage from a future tsunami. [ABSTRACT FROM AUTHOR]

We examined the effect of the coastal forest on tsunami sediment movement on the Sendai Plain, Japan, during the 2011 Tohoku tsunami using a numerical simulation of sediment transport. To account for the variable roughness coefficient in the coastal forest, a composite equivalent roughness coefficient was adopted. The simulated mean concentration of suspended sediment, wave height, flow velocity, and inundation limit were significantly reduced by the coastal forest. For fine to medium sand, the volumes of maximum deposition and erosion were reduced to 57–83% of those in the simulation without the coastal forest; these reductions were particularly notable for fine sand. The maximum extent and thickness of the sand layer were also reduced. The simulated sediment thickness and extent with the coastal forest for finer grain sizes roughly agreed with the observations, while the simulated results for coarser sand underestimated the observations. The reduction of sediment transport due to the coastal forest suggests that land use conditions and the vegetation environment at the time of a tsunami should be considered when studying historical and paleo-tsunamis using the geological evidence. [ABSTRACT FROM AUTHOR]

Business continuity plans (BCPs) can be effective and proactive countermeasures to respond flexibly to crises caused by unexpected natural disasters such as large tsunamis. BCP guidelines for fisheries are being issued by the Fisheries Agency (Japan) and the utilization of such BCPs has been spreading in Japan. Despite the need to promote the social implementation of BCPs in the fisheries industry, there is a lack of quantitative criteria for the tsunami damage threshold of various fishing ports and facilities. In this research, we surveyed the damage to the fishing facilities from the tsunami generated by the 2011 Tohoku-oki earthquake. Data were collected on the tsunami damage for various fishery facilities and used to establish criteria for tsunami damage thresholds. In addition, tsunami damage inferred from 1506 scenarios of tsunami computations was predicted probabilistically for a model region as the Nachi Katsu'ura Fishery Port in Wakayama Prefecture. The method we developed in this research makes it possible to assess the probabilistic tsunami damage by combining a tsunami hazard assessment method with criteria for damage occurrence for fishery port facilities and equipment. [ABSTRACT FROM AUTHOR]

Tsunamis caused by submarine landslides are not accompanied by seismic waves and thus may appear at the coast without warning. In this study, detailed bathymetric surveys with a multi-narrow beam echo sounder were used to map submarine landslides on the continental shelf near Cape Muroto, in the Nankai trough off southwestern Japan. One of the surveyed submarine landslides was selected to supply dimensions for the simulation of a submarine mass movement by a two-layer flow model in which the upper and lower layers correspond to seawater and turbidity currents, respectively. The time series of seafloor deformation during this simulated landslide was used as the boundary condition to drive a tsunami simulation. The results showed strong directivity effects during tsunami generation in which pushing-dominant (positive) tsunami waves propagated seaward, in the direction of the submarine landslide, and pulling-dominant (negative) tsunami waves propagated landward. Both types of waves were strongly modified by frequency dispersion. For pulling-dominant waves, a tsunami simulation that included dispersion (Boussinesq) terms predicted greater maximum tsunami heights than a non-dispersive tsunami simulation. To avoid underestimation of tsunami heights, we recommend including dispersion terms when modeling tsunamis caused by submarine landslides for disaster planning purposes. • Bathymetric survey shows detailed features of the submarine landslide. • Two-layer flow model estimates the submarine mass movement. • Tsunamis caused by the submarine landslide are deeply affected by dispersion effects. [ABSTRACT FROM AUTHOR]

Background: Complex segmentectomy creates several intricate intersegmental planes; however, it has not been fully established in lung cancer treatment. We compared the oncologic outcomes of complex segmentectomy and lobectomy through a large cohort, multicenter database using propensity score-matched analysis., Methods: We retrospectively analyzed data from 1517 patients with clinical stage I lung cancer with a solid component size 2.0 cm or less, who underwent surgical resection at 3 institutions between 2010 and 2018. Complex segmentectomy (n = 240) and location-adjusted lobectomy (n = 851) as well as surgical results were analyzed for all patients and their propensity score-matched pairs., Results: The prognosis of patients undergoing complex segmentectomy was not significantly different from that of patients undergoing lobectomy (5-year cancer-specific survival [CSS] rate, 96.4% versus 97.2%, P = .69; and 5-year recurrence-free interval [RFI] rate, 95.8% versus 93.4%, P = .19). This trend was also identified in subanalyses for pure solid tumors. However, there were major differences in clinicopathologic features between the 2 groups. After propensity score-matched analysis, proper matching of patients was ascertained. In 219 propensity score-matched pairs, long-term outcomes were similar between patients undergoing complex segmentectomy (5-year CSS, 96.0%; 5-year RFI, 95.5%) and lobectomy (5-year CSS, 97.8%; 5-year RFI, 95.9%). Propensity score-adjusted multivariable analysis for RFI revealed that prognosis associated with complex segmentectomy was comparable to the prognosis obtained with lobectomy (hazard ratio = 0.98; 95% confidence interval, 0.33-2.40; P = .98)., Conclusions: Complex segmentectomy provides acceptable oncologic outcomes in clinical stage I lung cancer treatment., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: Recurrence risk of resected lung adenocarcinoma is represented by pathological stage (pStage), histological subtype, and potentially by EGFR mutation. However, the relationship among these factors and their combined impact on prognosis are unclear., Materials and Methods: Using a multicenter database, we retrospectively investigated the prognostic impact of EGFR mutation status in relation to pStage and histological subtype in resected pN0-1M0 lung adenocarcinoma., Results: Among 1155 pN0-1M0 adenocarcinoma cases, pStage 0 and IA1-IB were confirmed predominantly in EGFR-positive cases. AIS, MIA, and lepidic predominant adenocarcinoma were also more frequently found in EGFR-positive cases and showed no/little recurrence regardless of EGFR mutation status. The 5-year recurrence-free survival (RFS) of papillary, acinar, solid, and micropapillary predominant adenocarcinoma was stratified by pStage (IA1-IB, IIA-IIIA) or histological malignant subtype (intermediate or high malignant subtype), and more finely subdivided by EGFR mutation status. Positive EGFR mutation cases showed worse RFS in both classifications. Low malignant subtype and pStage IA1-IB intermediate malignant subtype showed low frequency of recurrence. Whereas, in pStage IA1-IB high malignant subtype and pStage IIA-IIIA cases, EGFR-positive cases showed poorer 5-year RFS than EGFR-negative (49.6% and 75.6%, respectively, hazard ratio [HR] = 1.84, 95% CI = 1.38-7.42, p <  0.01) and multivariate analysis indicated positive EGFR mutation status was significantly related to poorer PRF (HR = 2.005, 95% CI = 1.029-3.906, p =  0.041)., Conclusion: EGFR mutation harbored primarily in early-stage or low-malignant histological subtypes with no/little recurrence. In pN0-1M0 adenocarcinoma with higher risk of recurrence, positive EGFR mutation cases showed worse RFS. EGFR mutation status enables better stratification of recurrence risk when considering pStage and histological malignant subtype., Competing Interests: Declaration of Competing Interest None. Financial/nonfinancial disclosures: None Other contributions: The authors would like to thank Editage (www.editage.jp) for English language editing., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objectives: To investigate the prevalence of chronic comorbidities and the use of comedications in people living with HIV (PLWH) and on antiretrovirals in Japan, by using a hospital claims database., Design: Observational, retrospective, cross-sectional study., Setting: A hospital claims database of Japanese hospitals that have advanced medical treatment capabilities (ie, advanced treatment hospitals, general hospitals, acute care hospitals), which include those providing acute and chronic care (excluding nursing homes or hospices)., Participants: A total of 1445 PLWH aged ≥18 years and with a prescription record of antiretrovirals between January 2010 and December 2015 were identified from the database., Outcome Measures: The number and types of chronic comorbidities, as well as the number and types of comedications, in different age groups of the PLWH., Results: The median (range) age of patients was 45 (18-90) years, and 90.4% were men. Of the 1445 patients, 972 (67.3%) had at least one chronic comorbidity. Common chronic comorbidities included lipid disorders (31.6%), diabetes (26.8%), hypertension (18.2%) and hepatitis B/C coinfection (18.2%). Patients in the older age groups had greater numbers of chronic comorbidities. The most common chronic comorbidities in the older age groups were hypertension, diabetes and lipid disorders. The majority of patients used at least one comedication, and those in the older age groups used greater numbers of comedications. The most common therapeutic category of comedication included antacids, antiflatulents and antiulcerants (31.7%). Of 151 malignancies reported in 117 patients, 84 were AIDS-defining cancers and 67 were non-AIDS-defining cancers., Conclusions: Chronic comorbidities and comedications were common among PLWH in Japan taking antiretrovirals; particularly among older patients, who more frequently used comedications. This suggests the need for giving special attention to the appropriate management of this patient population., Competing Interests: Competing interests: DJR, KI and KT are employees of MSD K.K., Tokyo, Japan. TN has received no funding for this study but received lecture fees from MSD K.K., Tokyo, Japan., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objectives: To quantify the risk of pneumococcal pneumonia (PP) and invasive pneumococcal disease (IPD) in adults aged ≥19 years with underlying medical conditions compared with healthy adults of the same age in Japan., Design: An observational, retrospective, cohort study using two healthcare claims databases in Japan: Japan Medical Data Center (JMDC) and Medical Data Vision (MDV) databases., Participants: A total of 10.4 million individuals, representing 9.3 million person-years of follow-up, were included in the analysis. Eleven medical conditions as well as PP and IPD were identified by the International Statistical Classification of Diseases and Related Health Problems version 10 diagnostic codes and/or local disease codes used in Japan., Primary Outcome Measures: Adjusted rate ratios (RRs) for PP and IPD in adults with a medical condition versus adults without any medical condition were calculated using multivariate Poisson regression models with age and/or sex as covariates., Results: In the JMDC and MDV databases, respectively, adults ≥19 years with a medical condition (RRs for PP: 3.3 to 13.4, 1.7 to 5.2; RRs for IPD: 12.6 to 43.3, 4.4 to 7.1), adults with two or more medical conditions (PP: 11.6, 2.8; IPD: 18.7, 5.8) and high-risk adults (PP: 12.9, 1.8; IPD: 29.7, 4.0) were at greater risk of PP and IPD compared with their healthy counterparts. Adults aged 50-64 years with an underlying medical condition (PP rate: 38.6 to 212.1 per 100 000 person-years) had a higher rate of PP than those aged ≥65 years without any condition (PP rate: 13.2 to 93.0 per 100 000 person-years)., Conclusions: Adults of all ages with an underlying medical condition are at greater risk of PP and IPD compared with adults without any medical condition. This risk increases with the number of underlying medical conditions. Our results support extending pneumococcal vaccination to younger adults with an underlying medical condition, especially those aged 50-64 years., Competing Interests: Competing interests: KI, AS and SK are employees of MSD K.K., a group of Merck Sharp & Dohme Corp., which is a subsidiary of Merck & Co., Inc. (Kenilworth, New Jersey, USA). KN and MA received research grants and lecture fees from MSD K.K. TP and MAK are employees of Merck & Co., Inc. Employees may hold stock and/or stock options in the company. The study sponsor, Merck & Co., Inc., and MSD K.K. reviewed the study design; participated in the collection, analysis and interpretation of the data; critically reviewed the report and decided to submit the paper for publication., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)