Human papillomavirus (HPV) types among Alaska native women attending a colposcopy clinic in Anchorage, Alaska, 2009-2011.

BACKGROUND: The first HPV vaccines licensed targeted two HPV types responsible for most cervical cancers. A 9-valent vaccine (9vHPV), targeting 5 additional types, was introduced in 2016 and is currently the only HPV vaccine available in the United States. Previous studies demonstrated high rates of HPV infection in Alaska Native (AN) women. We sought to measure prevalence of high risk HPV types in AN women undergoing colposcopy and to determine those preventable by vaccination. METHODS: For this cross-sectional study, we recruited women who were undergoing colposcopy for clinical indications at Alaska Native Medical Center to obtain cervical brush biopsy samples. Specimens were shipped to Atlanta, Georgia for DNA extraction, HPV detection, and typing using L1 PCR with type-specific hybridization to detect 37 HPV types. RESULTS: Four hundred eighty eight specimens from 489 women were tested. At least one HPV type was found in 458 (94%) specimens. Of 458 participants who were HPV positive, 332 (72%) had two or more types. At least one type targeted by 9vHPV was detected in 95% of participants with CIN 3 (21/22), 82% with CIN 2 (37/45), and 65% with CIN 1 (119/184). (p < 0.001) HPV 16 or 18 were detected in 77% (17/22) with CIN 3, 53% (24/45) with CIN 2, and 36% (67/184) with CIN 1. (p < 0.001). CONCLUSIONS: A substantial proportion of AN women attending colposcopy clinic had evidence of HPV 16/18 infection, as well as other high risk types targeted by 9vHPV. At least one 9vHPV type was detected in 62% of the participants overall, and 95% of participants with CIN3. AN women are expected to benefit from vaccination against HPV 16/18, and will have greater benefit from 9vHPV. Information from this study could be used to develop public health strategies to increase vaccine uptake, or to track HPV genotype prevalence over time.

Persistence of antibody to Hepatitis A virus 20 years after receipt of Hepatitis A vaccine in Alaska.

Hepatitis A vaccine is recommended for children ≥1 year old to prevent hepatitis A virus (HAV) infection. However, the duration of vaccine-induced immunity is unknown. We evaluated a cohort of Alaska Native persons 20 years after HAV vaccination. Children aged 3-6 years had been previously randomized to receive three doses of HAV vaccine (360 ELISA units/dose) at: (i) 0,1,2 months; (ii) 0,1,6 months; and (iii) 0,1,12 months. We measured anti-HAV antibody concentrations every 2-3 years; described geometric mean concentrations (GMC) and the proportion with protective antibody (≥20 mIU mL-1 ) over time; and modelled the change in GMC using fractional polynomial regression. Of the 144 participants, after 20 years 52 (36.1%) were available for the follow-up (17, 18, 17 children in Groups A, B and C, respectively). Overall, 46 (88.5%) of 52 available participants had anti-HAV antibody concentrations ≥20 mIU mL-1 , and overall GMC was 107 mIU mL-1 . Although GMC levels were lower in Group A (60; CI 34-104) than in Group B (110; CI 68-177) or Group C (184; CI 98-345) (B vs C: P=.168; A vs B/C: P=.011), there was no difference between groups after adjusting for peak antibody levels post-vaccination (P=.579). Models predicted geometric mean concentrations of 124 mIU mL-1 after 25 years, and 106 mIU mL-1 after 30 years. HAV vaccine provides protective antibody levels 20 years after childhood vaccination. Lower antibody levels in Group A may be explained by a lower initial peak response. Our results suggest a booster vaccine dose is unnecessary for at least 25-30 years.

Housing characteristics and indoor air quality in households of Alaska Native children with chronic lung conditions.

Alaska Native children experience high rates of respiratory infections and conditions. Household crowding, indoor smoke, lack of piped water, and poverty have been associated with respiratory infections. We describe the baseline household characteristics of children with severe or chronic lung disease participating in a 2012-2015 indoor air study. We monitored indoor PM2.5, CO2 , relative humidity %, temperature, and VOCs and interviewed caregivers about children's respiratory symptoms. We evaluated the association between reported children's respiratory symptoms and indoor air quality indicators using multiple logistic regression analysis. Compared with general US households, study households were more likely overcrowded 73% (62%-82%) vs 3.2% (3.1%-3.3%); had higher woodstove use as primary heat source 16% (9%-25%) vs 2.1% (2.0%-2.2%); and higher proportion of children in a household with a smoker 49% (38%-60%) vs 26.2% (25.5%-26.8%). Median PM2.5 was 33 µg/m3 . Median CO2 was 1401 ppm. VOCs were detectable in all homes. VOCs, smoker, primary wood heat, and PM2.5>25 µg/m3 were associated with higher risk for cough between colds; VOCs were associated with higher risk for wheeze between colds and asthma diagnosis. High indoor air pollutant levels were associated with respiratory symptoms in household children, likely related to overcrowding, poor ventilation, woodstove use, and tobacco smoke.

Nested case-control study: hepatocellular carcinoma risk after hepatitis B surface antigen seroclearance.

BACKGROUND: Hepatocellular carcinoma (HCC) risk after resolving chronic hepatitis B virus (HBV) infection is unclear. AIM: To compare HCC risk between Alaska Native (AN) patients with and without hepatitis B surface antigen (HBsAg) seroclearance. METHODS: We selected persons with (case-patients) and without (control-patients) HBsAg seroclearance from a cohort of 1346 chronically HBV-infected AN patients followed during 1982-2013. We attempted to match two control-patients/case-patient on sex, HBV genotype, and age. Person-years of follow-up for case-patients began on the date of HBsAg resolution and for control-patients began on the date equivalent to the cohort entry date plus the years of HBsAg duration for their corresponding case-patient. We compared HCC risk using a Cox proportional hazards model. RESULTS: The 238 case-patients (4 with HCC) and 435 control-patients (9 with HCC) were similar in age [P-value (P) = 0.30], sex (P = 0.53) and HBV genotype (P = 0.99). Case-patients had longer person-years of follow-up than control-patients (11.7 vs. 10.1 years; P = 0.04). The HCC rate/100 000 persons was similar between case- (132) and control-patients (178; P = 0.65). The adjusted hazard ratio comparing case- and control-patients was similar for HCC [0.7; 95% confidence interval (CI): 0.2-2.4], increased for each 1-year increment for age (1.1; CI: 1.0-1.1; P < 0.01), and was greater if the initial HBeAg was positive (3.5; CI: 1.1-11.0; P = 0.03). CONCLUSIONS: Hepatitis B surface antigen seroclearance was not associated with reduced HCC risk; the HCC risk estimates are limited by wide 95% confidence intervals. Persons meeting HCC surveillance indications prior to HBsAg seroclearance could benefit from continued surveillance after seroclearance.

Molecular epidemiology of serotype 19A Streptococcus pneumoniae among invasive isolates from Alaska, 1986-2010.

BACKGROUND: After the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in Alaska, the incidence of invasive pneumococcal disease (IPD) due to non-vaccine serotypes, particularly serotype 19A, increased. The aim of this study was to describe the molecular epidemiology of IPD due to serotype 19A in Alaska. METHODS: IPD data were collected from 1986 to 2010 through population-based laboratory surveillance. Isolates were serotyped by the Quellung reaction and MICs determined by broth microdilution. Genotypes were assessed by multilocus sequence typing. RESULTS: Among 3,294 cases of laboratory-confirmed IPD, 2,926 (89%) isolates were available for serotyping, of which 233 (8%) were serotype 19A. Across all ages, the proportion of IPD caused by serotype 19A increased from 3.5% (63/1823) pre-PCV7 (1986-2000) to 15.4% (170/1103) post-PCV7 (2001-2010) (p < 0.001); among children < 5 years of age, the proportion increased from 5.0% (39/776) to 33.0% (76/230) (p < 0.001). The annual incidence rate of IPD due to serotype 19A (all ages) increased from 0.73 cases pre-PCV7 to 2.56 cases/100,000 persons post-PCV7 (p < 0.001); rates among children < 5 years of age increased from 4.84 cases to 14.1 cases/100,000 persons (p < 0.001). Among all IPD isolates with reduced susceptibility to penicillin, 17.8% (32/180) were serotype 19A pre-PCV7 and 64% (121/189) were serotype 19A post-PCV7 (p < 0.001). Eighteen different sequence types (STs) were identified; ST199 or single locus variants of ST199 (n = 150) and ST172 (n = 59) accounted for the majority of isolates. Multidrug-resistant isolates were clustered in ST199 and ST320. CONCLUSION: While PCV13 should significantly reduce the burden of disease due to 19A, these data highlight the need to continue surveillance for IPD to monitor the effects of vaccination on the expansion and emergence of non-PCV strains.

Incidence of diabetes mellitus in a population-based cohort of persons with chronic hepatitis B virus infection.

To investigate the effect of hepatitis B virus (HBV) infection on the development of diabetes mellitus (DM), we compared DM incidence and characteristics of Alaska Native persons with and without HBV infection. From 1990 to 2010, there were 52 incident DM cases among 1309 persons with infection vs 4557 DM cases among 85 698 persons without infection (log-rank test, P = 0.20). Compared to infected persons without DM, those with DM were significantly older (57.0 vs 47.4 years, P < 0.001) and had higher body mass index (34.5 vs 28.4 kg/m(2) , P < 0.001). Genotype, immune active disease and the presence of cirrhosis were not associated with DM. In this population-based cohort with over 20 years of follow-up, there was no effect of HBV infection on DM development.

Serologic and clinical outcomes of 1536 Alaska Natives chronically infected with hepatitis B virus.

BACKGROUND: Knowledge of the outcome of chronic hepatitis B virus (HBV) infection is limited. OBJECTIVE: To determine the incidence of and risk factors for adverse events (hepatocellular carcinoma and end-stage liver disease) and clearance of hepatitis B e antigen (HBeAg) and surface antigen (HBsAg) in carriers of HBV. DESIGN: Population-based cohort study of hepatitis B carriers who were observed for a median of 12.3 years as part of an active surveillance program to detect carriers with hepatocellular carcinoma. SETTING: 126 communities in Alaska. PATIENTS: 1536 Alaska Natives with chronic hepatitis B. MEASUREMENTS: Bivariate comparisons, multivariable models, and other statistical methods were used to examine the relationships of risk factors to outcomes and clearance of HBeAg and HBsAg. RESULTS: 1536 chronic HBV carriers were followed up for 19 430 person-years from their first HBsAg-positive test result. At the first serologic test, 641 were HBeAg positive and 893 were anti-HBe positive. Older carriers were more likely than younger carriers to clear HBeAg (P < 0.001). The observed probability of clearing HBeAg within 10 years of diagnosis was 72.5%. Clearance of HBsAg occurred in 106 (7%) of all carriers and was positively associated with older age and positive result on initial anti-HBe test. The incidence of adverse events was 2.3 per 1000 carrier-years, and the incidence of hepatocellular carcinoma was 1.9 per 1000 carrier-years (2.3 in men and 1.2 in women). Risk for hepatocellular carcinoma increased with age, among those of Yupik Eskimo ethnicity, and among carriers who reverted from anti-HBe to HBeAg. CONCLUSION: In HBsAg-positive carriers, observed clearance of HBeAg was more than 70% during the first 10 years of follow-up.

Evaluation of the response to a booster dose of hepatitis B vaccine in previously immunized healthcare workers.

INTRODUCTION: Hepatitis B vaccination is recommended for all healthcare workers (HCW) at risk of exposure to infectious body fluids. However, the absolute duration of protection from immunization is unknown. The purpose of this randomized comparison trial was to determine how previously immunized HCW respond to different booster doses of hepatitis B vaccine. METHOD: Adult HCW (n=59) were classified by level of hepatitis B surface antigen (anti-HBs), either <10 milli-International Units per milliliter (mIU/ml) or 10-50 mIU/ml. Participants were then randomized to receive a 2.5 or 10 microg dose of hepatitis B vaccine. Evaluation of anti-HBs levels were conducted 10 to 14 days, one month and one year postbooster. RESULTS AND DISCUSSION: All participants responded to the booster dose with increased anti-HBs levels. At 14 days, mean anti-HBs levels were significantly higher for those with higher levels at baseline (P=0.004) and those receiving the 10 microg dose (P=0.016). At one month, those with higher anti-HBs levels at baseline and those receiving the 10 microg dose were significantly higher (P<0.01 for both). At one year, the increase for the higher dose was no longer statistically significant when examined by itself (P=0.081); statistical significance (P=0.021) was achieved after adjusting for anti-HBs level at baseline. For all participants, the geometric mean anti-HBs level was 2618 mIU/ml at 14 days, 2175 mIU/ml at one month and 88.9 mIU/ml at one year. At all time points the increase in anti-HBs levels represented an increase over the geometric mean baseline level of anti-HBs (7.4 mIU/ml). Hepatitis B immunized adults responded to a booster dose of hepatitis B vaccine from 3 to 13 yr postvaccination series. Data support current recommendations that immunized HCW do not require periodic antibody testing or vaccine boosters.

High prevalence of Helicobacter pylori in the Alaska native population and association with low serum ferritin levels in young adults.

Iron deficiency anemia is a common public health problem in the Alaska Native population. Yet, a clear etiology has eluded researchers for decades. Previous studies suggested a link between Helicobacter pylori infection, gastrointestinal blood loss due to hemorrhagic gastritis, and generalized iron deficiency anemia in adult Alaska Natives. Therefore, we examined the association between the prevalence of H. pylori-specific immunoglobulin G (IgG) and serum ferritin levels, a marker of iron deficiency. A random sample of 2,080 serum samples from Alaska Native residents drawn between 1980 and 1986 from residents in 13 regions was selected, and the samples were stratified by age, sex, and region. Overall, 75% were positive for H. pylori-specific IgG. The rate of H. pylori seropositivity increased with age; by age 14 years, 78% of the residents were positive. There were no gender differences in H. pylori seropositivity. However, marked regional differences were observed. Serum ferritin levels of <12 ng/ml were found most commonly among persons <20 years of age and among women of childbearing age. A significant association between low serum ferritin levels and prevalence of H. pylori-specific IgG was found, particularly for people aged less than 20 years. H. pylori may be a factor contributing to the iron deficiency anemia in the Alaska Native population.

Screening for hepatocellular carcinoma in Alaska natives infected with chronic hepatitis B: a 16-year population-based study.

The benefits of screening hepatitis B surface antigen (HBsAg)-positive carriers for hepatocellular carcinoma (HCC) in terms of long-term survival have not been established. We conducted a prospective 16-year, population-based cohort study to determine the impact of screening for HCC in 1,487 HBsAg-positive Alaska native carriers with alpha-fetoprotein (AFP) determinations every 6 months. Men and nonpregnant women with an elevated AFP level were evaluated for the presence of HCC by ultrasound (US) examination. The long-term survival rate for patients whose HCC was detected by the screening program was compared with a historical control group of Alaska native patients with HCC from the same population who were clinically diagnosed with HCC between 1969 and October 1982, through a National Cancer Institute-sponsored Cancer Registry. Between October 1982 and December 1998, 26,752 AFP determinations in HBsAg carriers were performed. One or more AFP elevations were found in 61 men and 39 nonpregnant women. HCC was diagnosed in 32 patients (24 men and 8 women). HCC tumors less than 6 cm were found in 23 patients; 22 patients had resections, and 1 patient refused a resection. Compared with 12 patients with hepatitis B virus (HBV)-related HCC diagnosed from 1969 to October 1982, before this program, the 5- and 10-year survival rate for the 32 patients with HCC were 42% (P =.008) and 30% (P =.07), respectively. Five- and 10-year tumor-free survival rates for carriers who had a normal AFP level on initial screening and subsequently developed HCC were 29% (P =.004) and 24% (P =.024), respectively. Screening of HBsAg carriers with semiannual AFP was effective in detecting most HCC tumors at a resectable stage and significantly prolonged survival rates when compared with historical controls in this population.

Experience with the prevention of invasive Haemophilus influenzae type b disease by vaccination in Alaska: the impact of persistent oropharyngeal carriage.

OBJECTIVES: To report the epidemiology of invasive Haemophilus influenzae type b (Hib) disease in high-risk Alaska Native infants before and after universal infant Hib vaccination and evaluate an increase in invasive Hib disease in 1996 after changing Hib vaccine type. STUDY DESIGN: Statewide laboratory surveillance for invasive Hib disease has been conducted since 1980. Three cross-sectional Hib carriage studies were conducted in 1997 and 1998. RESULTS: The invasive Hib disease rate in Alaska Natives decreased from 332 cases per 100,000 children <5 years old in 1980-1991 to 17:100,000 in 1992-1995 but increased primarily in rural areas to 57.9:100,000 after a switch in Hib vaccine types. Carriage studies in 5 rural Alaska Native villages showed oropharyngeal Hib carriage as high as 9.3% in children aged 1 to 5 years; in contrast, carriage in urban Alaska Native children was <1%. CONCLUSIONS: Although Hib disease has decreased in Alaska, the rate of Hib disease and carriage in rural Alaska Natives did not decrease to the same extent as in non-Natives and urban Alaska Natives. Use of polyribosylribitol phosphate-outer-membrane protein conjugate vaccine for the first vaccine dose is critical to disease control in this population with continued transmission in infants <6 months of age. The ability to eliminate Hib carriage and disease may be affected by population characteristics, vaccination coverage, and Hib vaccine type used. This may pose a challenge to global elimination of Hib.

Serotype distribution and antimicrobial resistance patterns of invasive isolates of Streptococcus pneumoniae: Alaska, 1991-1998.

From January 1991 through December 1998, a total of 1046 pneumococcal isolates were received from 23 laboratories participating in the statewide surveillance system. Of these, 1037 were recovered from normally sterile sites (blood and cerebrospinal and pleural fluid) and were available for serotyping and susceptibility testing. Ninety-two percent of these isolates were serotypes represented in the 23-valent pneumococcal polysaccharide vaccine. Serotypes in the 7-valent pneumococcal conjugate vaccine (4, 6B, 9V, 14, 18C, 19F, and 23F) were recovered from 72% of Alaska Natives and 84% of non-Native children <5 years old with invasive disease. Statewide, 7.3% and 3.2% of isolates had intermediate and high levels of resistance to penicillin, respectively; 9.2% were resistant to erythromycin (minimal inhibitory concentration, >/=1 microg/mL) and 19% to trimethoprim/sulfamethoxazole (minimal inhibitory concentration, >/=4/76 microg/mL). Twelve percent of invasive isolates were resistant to >/=2 classes of antibiotics; of these, serotype 6B accounted for 33%, and 63% were recovered from children <5 years old.

Immunogenicity of a heptavalent pneumococcal conjugate vaccine in Apache and Navajo Indian, Alaska native, and non-native American children aged <2 years.

High rates of invasive pneumococcal disease have been described among infants living in various Native American communities. In this study, we evaluated the immunogenicity of a 7-valent pneumococcal vaccine consisting of serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F covalently linked to the outer membrane protein complex of Neisseria meningitidis in Apache and Navajo Indian, Alaska Native, and non-Native American children. The vaccine was administered at ages 2, 4, and 6 months; a booster dose was given at age 15 months. Levels of serotype-specific immunoglobulin G (IgG) were measured by a standardized enzyme-linked immunosorbent assay. The responses after 3 primary doses of vaccine were similar in all 3 groups of children, except for those to serotypes 14 and 23F. One month after the booster dose, geometric mean concentrations (GMCs) of serotype-specific IgG antibodies increased significantly in all 3 groups of children, compared with GMCs of IgG antibodies to pneumococcal serotypes before the booster dose.

Invasive Haemophilus influenzae disease in Alaskan residents aged 10 years and older before and after infant vaccination programs.

CONTEXT: The introduction of Haemophilus influenzae type b (Hib) vaccination of children has led to a decline in incidence of Hib disease in young Alaskan children. However, the impact of vaccination on unimmunized Alaskan adolescents and adults has not been studied. OBJECTIVE: To characterize trends in incidence of and mortality due to invasive H influenzae disease in Alaskan residents aged 10 years and older prior to and after the introduction of a statewide Hib infant vaccination program. DESIGN AND SETTING: Population-based, descriptive correlational study conducted 1980-1996 in Alaska. SUBJECTS: One hundred twenty-nine individuals (31 Alaska Natives and 98 nonnative Alaska residents) aged 10 years and older in whom H influenzae was cultured from a normally sterile site. MAIN OUTCOME MEASURES: Incidence of H influenzae infection before (1980-1990) vs after (1991-1996) vaccination program initiation; serotype, biotype, and beta-lactamase production of isolates. RESULTS: The overall annual incidence of invasive H influenzae in those aged 10 years and older declined 33%, from 2.1 per 100,000 persons per year to 1.4 per 100,000 persons per year (P=. 03) after initiation of statewide infant Hib vaccination programs in 1991. This reduction appeared to be the result of a decrease in serotype b disease (82%; P<.001). Infection with other H influenzae serotypes and nontypeable strains increased from 0.5 per 100,000 persons per year to 1.1 per 100,000 persons per year (P=.01). Incidence declined from 4.2 per 100,000 persons per year to 1.2 per 100,000 persons per year in Alaska Natives (P=.005) and from 1.7 per 100,000 persons per year to 1.4 per 100,000 persons per year in nonnative Alaska residents (P=.37). Pneumonia (43%), sepsis (26%), and meningitis (16%) were the most common clinical presentations. Alcohol/drug abuse was comorbid in 15% of patients, while 13% of patients were pregnant women. beta-Lactamase production occurred in 35% of isolates and was stable throughout the surveillance. The overall case-fatality rate was 15%. CONCLUSION: The overall statewide incidence of invasive H influenzae infections in unimmunized persons aged 10 years and older decreased after the initiation of an infant Hib vaccine program, perhaps by decreasing Hib carriage in child reservoirs. An increase in non-serotype b strains was observed. This trend justifies the need for continued surveillance of invasive disease caused by H influenzae. JAMA. 2000.

Bronchiectasis in Alaska Native children: causes and clinical courses.

Although bronchiectasis has become a rare condition in U.S. children, it is still commonly diagnosed in Alaska Native children in the Yukon Kuskokwim Delta. The prevalence of bronchiectasis has not decreased in persons born during the 1980s as compared with those born in the 1940s. We reviewed case histories of 46 children with bronchiectasis. We observed that recurrent pneumonia was the major preceding medical condition in 85% of patients. There was an association between the lobes affected by pneumonia and the lobes affected by bronchiectasis. Eight (17%) patients had surgical resection of involved lobes. We conclude that the continued high prevalence of bronchiectasis appears to be related to extremely high rates of infant and childhood pneumonia. Pediatr Pulmonol. 2000;29:182-187. Published 2000 Wiley-Liss, Inc.

Elimination of new chronic hepatitis B virus infections: results of the Alaska immunization program.

An immunization assessment and a serologic survey were conducted to evaluate the effectiveness of a hepatitis B immunization program in eliminating hepatitis B virus (HBV) transmission among Alaska Natives in a region in which HBV infection is endemic. Hepatitis B vaccine coverage was 93% among 567 children

Bacterial pathogens in chronic otitis media with effusion in Alaska Native children.

This study examined the bacterial pathogens and the presence of possible risk factors for the development of chronic otitis media with effusion (OME) in a group of Alaska Native children. Middle ear aspirates were collected from 128 children < 6 years of age requiring tympanocentesis between 1987 and 1989. Bacterial pathogens were cultured from 40% of 209 fluids. Predominant isolates, after contamination of the outer ear was controlled for, were Haemophilus influenzae (21%; 84% of these were nontypeable), Streptococcus pneumoniae (8.1%; serotypes 6B, 10A, 11A, 14, 18B, 18C, 19A, and 23F), Staphylococcus epidermidis (3.8%), and Moraxella (Brahmanella) catarrhalis (2.9%). Pneumococcal-C-polysaccharide (PnC) was detectable in 3 of 135 (2.2%) aspirates that did not grow Streptococcus pneumoniae. Combining culture and PnC assay results evidence of pneumococcal infection was found in almost 10% of aspirates tested. There was not a significant difference in the number of episodes of acute otitis media after the first year of life based on the age at the first episode (< 6 mo, > or = 6 mo). However, 88% of infants in the study had their first acute otitis media episode before 1 year of age.

Severe respiratory syncytial virus disease in Alaska native children. RSV Alaska Study Group.

Hospitalization rates for respiratory syncytial virus (RSV) infection range from 1 to 20/1000 infants. To determine the rate and severity of RSV infections requiring hospitalization for infants in the Yukon-Kuskokwim (YK) Delta of Alaska, a 3-year prospective surveillance study was conducted. The annual rate of RSV hospitalization for YK Delta infants <1 year of age was 53-249/1000. RSV infection was the most frequent cause of infant hospitalization. RSV disease severity did not differ among non-high-risk infants in the YK Delta and at Johns Hopkins Hospital (JHH). On average, 1/125 infants born in the YK Delta required mechanical ventilation for RSV infection. During the peak season, approximately $1034/child <3 years of age was spent on RSV hospitalization in the YK Delta. In YK Delta infants