We studied 54,178 adults with type 2 diabetes who had been on a GLP-1 medication for at least 90 days, experienced improvement in their HbA1c results while on the treatment, and subsequently stopped the GLP-1. We measured the absolute change in HbA1c between the value closest to the GLP-1 end date and the value closest to three, six, nine, and twelve months after stopping. HbA1c change was categorized as improved further, kept at least some of the improvement, or worsened to higher levels than the pre-GLP-1 baseline.

Three months after stopping a GLP-1, most patients had sustained or even improved upon their on-treatment HbA1c reduction, as seen in Figure 1. Of the patients with an HbA1c result at three months, 40% had an HbA1c lower than when they discontinued treatment, and another 48% kept at least some of their improvement. Just 12% had an HbA1c that was worse than their pre-GLP-1 baseline.

The pattern of durable glycemic improvement persisted over the full year of follow-up, though with a gradual shift over time. By six months, the proportion of patients with further HbA1c improvement had decreased to 34%, while those whose HbA1c was worse than their pre-GLP-1 level grew to 16%. At nine and twelve months the distribution continued to shift modestly, with 33% still showing further improvement, and 20% and 21% worse than their pre-GLP-1 level, respectively. Even at one year, roughly four in five patients had not returned to their pre-treatment HbA1c level.

While the overall distribution shifted gradually over time, individual patients’ early HbA1c trajectories were a strong predictor of where they would be at one year. Patients whose HbA1c was lower than their pre-GLP-1 level at three months most often had improvement at twelve months as well (55%). Patients whose HbA1c had already become worse than their pre-GLP-1 baseline at three months were most likely to remain in that category at twelve months (50%), though 25% had improved to below their pre-GLP-1 level by twelve months.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientist. The two teams came to similar conclusions. Graphics by Brian Olson.

1. Vahratian A, Warren A. GLP-1 injectable use among adults with diagnosed diabetes: United States, 2024. NCHS Data Brief. 2025;(537). https://www.cdc.gov/nchs/products/databriefs/db537.htm. Accessed March 2026.
2. Tsipas S, Khan T, Loustalot F, Myftari K, Wozniak G. Spending on glucagon-like peptide-1 receptor agonists among US adults. JAMA Netw Open. 2025;8(4):e252964. doi:10.1001/jamanetworkopen.2025.2964
3. Rodriguez PJ, Zhang V, Gratzl S, et al. Discontinuation and reinitiation of GLP-1 receptor agonists. JAMA Netw Open. 2025;8(1):e2457349. doi:10.1001/jamanetworkopen.2024.57349
4. Gasoyan H, Butsch WS, Schulte R, et al. GLP-1 receptor agonist discontinuation among patients with obesity and/or type 2 diabetes. JAMA Netw Open. 2024;7(5):e2413172. doi:10.1001/jamanetworkopen.2024.13172
5. Bartelt K, Deckert J, Franklin B, Barkley E. Two Years After Stopping GLP-1s, Most Patients Sustain at Least Some Weight Loss. Epic Research. https://epicresearch.org/articles/two-years-after-stopping-glp-1s-most-patients-sustain-at-least-some-weight-loss. Accessed on April 21, 2026.
6. Tzang CC, Wu PH, Luo CA, et al. Metabolic rebound after GLP-1 receptor agonist discontinuation: a systematic review and meta-analysis. EClinicalMedicine. 2025;90:103680. doi:10.1016/j.eclinm.2025.103680

To understand how scarlet fever rates changed among children from 2018 through 2025 and whether children diagnosed with scarlet fever were more likely to develop complications than those with strep throat alone, we studied 61 million pediatric patients who had encounters between January 2018 and December 2025.

Before the COVID-19 pandemic, scarlet fever rates among pediatric patients followed a consistent seasonal pattern, peaking between 19 and 24 per 100,000 patients with a visit in Q1 each year. Rates plummeted during the pandemic, falling to fewer than 3 per 100,000 through 2020 and 2021. By 2023, Q1 rates rebounded sharply, rising to around 47 per 100,000 in 2023 and 2024. Rates declined substantially by 2025 with the Q1 peak reaching only 18.9 per 100,000.

Next, we evaluated the relationship between scarlet fever and strep-related complications, such as rheumatic fever and meningitis. We accounted for demographics, rurality and social vulnerability based on the patient’s most recently documented address, and relevant comorbidities.

Compared to children diagnosed with strep throat who did not have scarlet fever, those diagnosed with scarlet fever were 21% more likely to experience a strep-related complication within six weeks, as seen in Figure 2.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 4,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Brian Olson.

1. About Strep Throat. U.S. Centers for Disease Control and Prevention. January 15, 2026. https://www.cdc.gov/group-a-strep/about/strep-throat.html. Accessed March 24, 2026.
2. Clinical guidance for Scarlet fever. U.S. Centers for Disease Control and Prevention. August 5, 2025. https://www.cdc.gov/group-a-strep/hcp/clinical-guidance/scarlet-fever.html. Accessed February 17, 2026.
3. Brouwer S, Rivera-Hernandez T, Curren BF, et al. Pathogenesis, epidemiology and control of Group A Streptococcus infection. Nat Rev Microbiol. 2023;21(7):431-447. doi:10.1038/s41579-023-00865-7
4. Increased incidence of scarlet fever and invasive Group A Streptococcus infection – multi-country. World Health Organization. https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON429. Accessed February 17, 2026.
5. Increase in invasive group A strep infections, 2022-2023. U.S. Centers for Disease Control and Prevention. February 2, 2023. https://archive.cdc.gov/www_cdc_gov/groupastrep/igas-infections-investigation.html. Accessed February 17, 2026.

The GLP-1 utilization tracker reports prescriptions per 100,000 patients for each GLP-1, and the BMI tracker reports the distribution of U.S. adults across BMI categories.

GLP-1 prescribing has grown substantially across the tracker’s window, with prescriptions per 100,000 U.S. adults rising from 1,884 in the second quarter of 2021 to 8,819 in the first quarter of 2026. The composition of GLP-1 prescribing changed markedly over the period. In 2021, the most prescribed agents were semaglutide (about 680 per 100,000) and dulaglutide (about 790 per 100,000). By the first quarter of 2026, tirzepatide had become the most frequently prescribed agent at roughly 4,700 prescriptions per 100,00 patients, and semaglutide had grown to around 3,900 per 100,000. Use of older agents declined as the newer drugs displaced them.

BMI distribution has shifted modestly toward lower weight categories over the same period, with the change concentrated in the second half of the period. The share of U.S. adults classified as obese was 42.3% in the second quarter of 2021 and remained near that level through 2022 before declining to 40.7% by the first quarter of 2026. Over the same window, the healthy weight share rose from 25.1% to 25.6%.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 304 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. Both trackers will be refreshed quarterly.

1. Adult obesity facts. U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/obesity/adult-obesity-facts/index.html. Accessed May 1, 2026.
2. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med. 2021;384(11):989-1002. doi:10.1056/NEJMoa2032183
3. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022;387(3):205-216. doi:10.1056/NEJMoa2206038

To understand how preoperative BMI changes across a range of starting weight categories relate to the risk of surgical site infections and mechanical failures after hip and knee replacement surgery, we studied more than one million adult patients who had one of these procedures between January 2017 and September 2025. We classified patients into five groups based on the percentage change in their BMI between a reading from the year prior to surgery and their BMI reading from within a month of the procedure: 2% or more gain, stable (within 2% change), 2% to less than 10% loss, 10% to less than 20% loss, and 20% or more loss. These weight change groups were further stratified by starting BMI class (overweight, obese class 1, obese class 2, and severely obese), comparing each weight change group to patients in the same class whose weight remained stable. We accounted for demographics, Area Deprivation Index based on most recently documented address, and relevant comorbidities (such as diabetes, obstructive sleep apnea, cardiovascular disease, hypertension, and conditions suggesting immunosuppression).

Compared to patients in the same starting BMI class whose weight remained stable, the likelihood of surgical site infection after knee replacement increased with greater preoperative weight loss, with the steepest gradient among overweight (BMI 25-<30) and class 1 obesity (BMI 30-<35) patients, as seen in Figure 1. Among overweight patients, each level of additional weight loss corresponded to a progressively higher likelihood of infection, reaching more than six times as likely among those who lost 20% or more. Among patients with class 1 obesity, losses of 20% or more were associated with more than four times the likelihood. The gradient was less steep at higher starting BMI classes; among severely obese (BMI 40+) patients, losses of 20% or more were associated with only a 27% higher likelihood. Weight gain was also associated with modestly elevated likelihood across all BMI classes.

Compared to patients in the same BMI class whose weight remained stable, preoperative weight loss was also associated with higher likelihood of surgical site infection after hip replacement among overweight, class 1, and class 2 obesity patients, as seen in Figure 2. Among overweight patients, losses of 20% or more were associated with a 169% higher likelihood, and among class 1 obesity patients, a 152% higher likelihood. Among severely obese patients, however, preoperative weight loss was not associated with a statistically significant change in infection likelihood at any level of loss. Weight gain of 2% or more was associated with a modestly higher likelihood across all BMI classes, ranging from a 31% to 38% increase.

Compared to patients in the same BMI class whose weight remained stable, preoperative weight loss showed associations with mechanical failure after knee replacement that was dependent on starting BMI. Among patients with an overweight BMI, losses of 20% or more were associated with a 128% higher likelihood, and among class 1 obesity patients, a 102% higher likelihood. Among severely obese patients, greater weight loss corresponded to a lower likelihood of mechanical failure, though not statistically significantly. Losses under 10% showed little meaningful association for any BMI class.

Compared to patients in the same BMI class whose weight remained stable, the relationship between preoperative weight change and mechanical failure after hip replacement was the most variable of the four outcomes. Among overweight patients, losses of 10–20% were associated with a 103% higher likelihood and losses of 20% or more with a 138% higher likelihood, as seen in Figure 4. Among class 1 obesity patients, losses of 20% or more were associated with a 169% higher likelihood. Among severely obese patients, weight loss was not associated with higher mechanical failure likelihood at any level.

This study measured the association between preoperative weight change and surgical complications but cannot distinguish whether weight loss itself influenced outcomes or whether it reflects underlying factors, such as illness, frailty, or nutrition status, which might independently affect surgical risk. Additionally, obesity carries well-established risks beyond those studied here.^1,3

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Brian Olson.

1. Kerkhoffs GM, Servien E, Dunn W, Dahm D, Bramer JA, Haverkamp D. The influence of obesity on the complication rate and outcome of total knee arthroplasty: a meta-analysis and systematic literature review. J Bone Joint Surg Am. 2012;94(20):1839-1844. doi:10.2106/JBJS.K.00820
2. Seward MW, Grimm JA, Hannon CP, Bedard NA, Berry DJ, Abdel MP. Weight Loss Before Total Hip Arthroplasty Was Not Associated with Decreased Postoperative Risks. J Bone Joint Surg Am. 2025;107(8):849-857. doi:10.2106/JBJS.24.01110
3. Inacio MC, Kritz-Silverstein D, Raman R, et al. The risk of surgical site infection and re-admission in obese patients undergoing total joint replacement who lose weight before surgery and keep it off post-operatively. Bone Joint J. 2014;96-B(5):629-635. doi:10.1302/0301-620X.96B5.33136

To understand the relationship between opioid prescriptions and functional recovery after joint arthroplasty, we studied 1,296 adults who underwent THA and 1,960 adults who underwent TKA between January 2022 and January 2025 with recorded baseline and follow-up scores. We excluded patients who had active opioid prescriptions beyond 30 days after surgery, underwent revision surgery or bilateral same-day procedures, or had another arthroplasty before the follow-up score was obtained. Patients who received a short-term opioid prescription were matched with those who did not receive an opioid prescription based on surgery type and baseline functional score. Because of this, both groups started with identical score profiles.

Three months after hip replacement surgery, both those who received short-term opioids and those who received no opioids showed substantial improvement. Among patients who received an opioid prescription, 69.8% scored 70 or greater at three months, compared to 59.3% of patients who did not receive opioids. The opioid group also had fewer patients remaining in the lowest-scoring range at three months (1.5% vs. 3.7%).

A similar but more modest pattern emerged among knee replacement patients. The proportion reaching scores of 70 or greater was comparable between groups: 35.5% among patients who received opioids and 31.4% among those who did not. Both groups saw sharp reductions in the share of patients with the worst functional scores, dropping from about 10% before surgery to under 3% at three months.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Brian Olson.

1. Hannon CP, Fillingham YA, Hamilton WG, Della Valle CJ. Multimodal Analgesia and Anesthesia: Enabling Safe and Rapid Recovery for Total Joint Arthroplasty Patients. J Arthroplasty. 2022;37(9):1669-1670. doi:10.1016/j.arth.2022.07.016
2. Goplen CM, Verbeek W, Kang SH, et al. Preoperative opioid use is associated with worse patient outcomes after Total joint arthroplasty: a systematic review and meta-analysis. BMC Musculoskelet Disord. 2019;20(1):234. Published 2019 May 18. doi:10.1186/s12891-019-2619-8
3. Lyman S, Lee YY, Franklin PD, Li W, Mayman DJ, Padgett DE. Validation of the HOOS, JR: a short-form Hip Replacement Survey. Clin Orthop Relat Res. 2016;474(6):1472-1482.
4. Lyman S, Lee YY, Franklin PD, Li W, Cross MB, Padgett DE. Validation of the KOOS, JR: a short-form Knee Arthroplasty Outcomes Survey. Clin Orthop Relat Res. 2016;474(6):1461-1471.

For the prescribing trends analysis, we examined 279 million primary care encounters that occurred between 2015 and 2025 among adults aged 40 and older. Patients with conditions that would indicate aspirin use for secondary prevention (such as coronary artery disease, prior stroke, or peripheral artery disease) as well as those for whom aspirin was contraindicated due to allergy or pregnancy were excluded. 

The share of visits where low-dose aspirin appeared on the medication list fell from a peak of 7.4% in mid-2018 to 3.2% by the end of 2025, a reduction of more than half. The decline has been steady since 2018, and the downward trend was consistent across all demographic subgroups. Notably, adults aged 80 and older, the group current guidelines most strongly recommend against starting on aspirin, still had the highest prevalence at 5.7% in late 2025, down from a peak of 10.9%.

For the bleeding risk analysis, we studied 625,742 patients aged 40 and older who received their first prescription for daily low-dose aspirin between 2017 and 2025, excluding those with a prior bleeding diagnosis, secondary prevention indications, or pregnancy. To isolate the effect of aspirin itself on bleeding, we needed a comparison group that was similar in health profile but not taking aspirin. We matched aspirin-prescribed patients with those who had an allergy to aspirin documented, a group unlikely to be using aspirin. Matching was based on demographics, start year, comorbidities, and ulcer medication use.

Aspirin’s association with major bleeding was concentrated in adults 75 and older, consistent with findings from earlier clinical trials.^2,3,4 Patients aged 75–79 who used aspirin had a 33% higher risk of major bleeding compared to same-aged patients with a documented aspirin allergy, and those aged 80 and above had a 37% higher risk. For adults under 75, there was no significant difference in bleeding risk between aspirin users and those with an allergy to aspirin.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientist. The two teams came to similar conclusions. Graphics by Brian Olson.

1. Bibbins-Domingo K; US Preventive Services Task Force. Aspirin use for the primary prevention of cardiovascular disease and colorectal cancer: US Preventive Services Task Force recommendation statement. Ann Intern Med. 2016;164(12):836-845. doi:10.7326/M16-0577
2. Gaziano JM, Brotons C, Coppolecchia R, et al. Use of aspirin to reduce risk of initial vascular events in patients at moderate risk of cardiovascular disease (ARRIVE): a randomised, double-blind, placebo-controlled trial. Lancet. 2018;392(10152):1036-1046. doi:10.1016/S0140-6736(18)31924-X
3. ASCEND Study Collaborative Group. Effects of aspirin for primary prevention in persons with diabetes mellitus. N Engl J Med. 2018;379(16):1529-1539. doi:10.1056/NEJMoa1804988
4. McNeil JJ, Wolfe R, Woods RL, et al. Effect of aspirin on cardiovascular events and bleeding in the healthy elderly. N Engl J Med. 2018;379(16):1509-1518. doi:10.1056/NEJMoa1805819
5. Arnett DK, Blumenthal RS, Gersh B, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;140(11):e596-e646. doi:10.1161/CIR.0000000000000678
6. Davidson KW, Barry MJ, Mangione CM, et al. Aspirin use to prevent cardiovascular disease: US Preventive Services Task Force recommendation statement. JAMA. 2022;327(16):1577-1584. doi:10.1001/jama.2022.4983

We studied more than 1 million adults newly treated for essential hypertension between January 1, 2017, and June 30, 2025, after a series of elevated blood pressure readings. We excluded patients with secondary hypertension, those who were pregnant, and those with prior antihypertensive medication use. We compared the likelihood of achieving controlled blood pressure (systolic blood pressure at or below 140 mmHg) at 30 to 59 days, 60 to 89 days, and 90 to 180 days between patients prescribed once-daily versus multi-dose regimens. We accounted for demographics, social vulnerability based on most recent ZIP code, and baseline systolic blood pressure.

Once-daily dosing regimens were most common across all four antihypertensive classes, as shown in Figure 1. Multi-daily dosing accounted for just over 1% of ACE inhibitor, ARB, and calcium channel blocker prescriptions, but 23.8% of beta blocker prescriptions.

Among patients prescribed ACE inhibitors, ARBs, and calcium channel blockers, those on once-daily regimens were more likely to achieve blood pressure control compared to multiple-dose regimens of the same medication classes. These differences emerged as early as 30 days after the prescription started and persisted through 180 days, as seen in Figure 2. In contrast, beta blockers showed a decrease in early blood pressure control when prescribed once per day, though there was no significant difference at 90 to 180 days.

Multi-dose prescribing for newly hypertensive patients is uncommon among most of the medications studied. The patients who did receive multi-dose regimens might have other factors that influenced the prescribing pattern that were not accounted for. Observed associations represent prescribing patterns rather than confirmed medication exposure or use.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientist. The two teams came to similar conclusions. Graphics by Brian Olson.

1. Lee JS, Segura Escano R, Therrien NL, et al. Antihypertensive Medication Adherence and Medical Costs, Health Care Use, and Labor Productivity Among People With Hypertension. J Am Heart Assoc. 2024;13(21):e037357. doi:10.1161/JAHA.124.037357
2. Srivastava K, Arora A, Kataria A, Cappelleri JC, Sadosky A, Peterson AM. Impact of reducing dosing frequency on adherence to oral therapies: a literature review and meta-analysis. Patient Prefer Adherence. 2013;7:419-434. Published 2013 May 20. doi:10.2147/PPA.S44646
3. Laliberté F, Bookhart BK, Nelson WW, et al. Impact of once-daily versus twice-daily dosing frequency on adherence to chronic medications among patients with venous thromboembolism. Patient. 2013;6(3):213-224. doi:10.1007/s40271-013-0020-5

We studied 2 million U.S. patients who sought medical care for RSV between January 2017 and January 2026. For each patient encounter, we classified the highest level of care into four mutually exclusive categories: ICU admission, hospital admission, emergency department (ED) visit, or office visit. This acuity distribution was computed for the overall population and stratified by age group: under 2, 2–4, 5–17, 18–49, 50–64, 65–74, and 75 years and older.

The distribution of RSV encounters across care settings has shifted markedly over the past nine years. In January 2017, 8.2% of RSV encounters resulted in ICU admission, 21.9% in hospital admission, 29.4% in ED visits, and 40.6% in office visits, as seen in Figure 1. By January 2026, those proportions had shifted to 3.8% ICU, 11.8% admission, 45.0% ED, and 39.4% office visits. Notably, the office visit share remained relatively steady throughout the study period (40.6% in January 2017 and 39.4% in January 2026) indicating that the shift toward ED care came primarily from hospitalizations and ICU admissions, not from patients who would otherwise have been seen in outpatient settings. This lower-acuity pattern began during the COVID-19 pandemic and has persisted through subsequent seasons.

We additionally looked at this distribution by age group. Among adults aged 75 and older, hospitalizations and ICU admissions accounted for 79.0% of RSV encounters in January 2017 but fell to 47.2% by January 2026. The ED share in this group more than tripled over that period, growing from 6.9% to 24.6%. Adults aged 65–74 followed a similar trajectory. For children under 2 years old, ICU admissions declined from 7.4% of cases in January 2017 to 3.8% in January 2026, and ED visits grew from 31.2% to 47.6%. Children aged 2–4 had a similar pattern. School-aged children (ages 5–17) saw the largest proportional decline in inpatient care: their combined hospitalization and ICU share fell from 37.3% in January 2017 to 6.0% in January 2026.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 2,000 hospitals and more than 47,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Brian Olson.

1. About RSV. U.S. Centers for Disease Control and Prevention. December 30, 2025. https://www.cdc.gov/rsv/about/index.html. Accessed March 2, 2026.
2. Hamid S, Winn A, Parikh R, et al. Seasonality of Respiratory Syncytial Virus – United States, 2017-2023. MMWR Morb Mortal Wkly Rep. 2023;72(14):355-361. Published 2023 Apr 7. doi:10.15585/mmwr.mm7214a1
3. Agha R, Avner JR. Delayed Seasonal RSV Surge Observed During the COVID-19 Pandemic. Pediatrics. 2021;148(3):e2021052089. doi:10.1542/peds.2021-052089
4. Butler S, Barkley E. RSV Rebounds Off-Season, but Influenza Is Still a No-Show. Epic Research. https://epicresearch.org/articles/rsv-rebounds-off-season-but-influenza-is-still-a-no-show. Accessed March 2, 2026.
5. Rios-Guzman E, Simons LM, Dean TJ, et al. Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic. Nat Commun. 2024;15(1):3374. Published 2024 Apr 20. doi:10.1038/s41467-024-47757-9
6. FDA approves first respiratory syncytial virus (RSV) vaccine. U.S. Food and Drug Administration. May 4, 2023. Accessed December 26, 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-first-respiratory-syncytial-virus-rsv-vaccine. Accessed March 2, 2026.
7. Bartelt K, Deckert J, Gracianette M, Barkley E. RSV Vaccine Can Prevent More Than 70% of RSV Infections, ED Visits, and Admissions Among Older Adults. Epic Research. https://epicresearch.org/articles/rsv-vaccine-can-prevent-more-than-70-of-rsv-infections-ed-visits-and-admissions-among-older-adults. Accessed on April 6, 2026.
8. FDA approves first vaccine for pregnant individuals to prevent RSV in infants. U.S. Food and Drug Administration. Published August 21, 2023. https://www.fda.gov/news-events/press-announcements/fda-approves-first-vaccine-pregnant-individuals-prevent-rsv-infants. Accessed March 2, 2026.
9. Bartelt K, Gasser J, Higgs E, Gracianette M, Barkley E. Maternal RSV Vaccine Effective in Reducing RSV Infections and Hospitalizations in Infants. Epic Research. https://epicresearch.org/articles/maternal-rsv-vaccine-effective-in-reducing-rsv-infections-and-hospitalizations-in-infants. Accessed on April 6, 2026.

We studied 10,260 patients aged 2 and older who received an influenza vaccine between August 1, 2025, and January 31, 2026, and who resided in one of the 34 states where the at-home nasal influenza vaccine was available. Patients were classified by whether they received the nasal vaccine at home or in clinic. We matched patients on vaccination month, race and ethnicity, and age. We additionally accounted for sex, social vulnerability and rurality based on most recent address, prior-year healthcare utilization, BMI classification, pregnancy status, and comorbidities.

We found that patients who received the at-home nasal vaccine were 37.4% less likely to be diagnosed with an influenza infection during the 2025/2026 influenza season compared to those who received the in-clinic nasal vaccine, as seen in Figure 1.

The unadjusted infection rate was 1.1% among the at-home vaccinated group compared to 1.7% among the in-clinic vaccinated group. While this difference favors the at-home group, its interpretation requires careful consideration of how the two populations differ. Both groups received the same vaccine; the difference lies in the setting of administration. As such, similar effectiveness would be expected, and the difference might indicate that there are meaningful differences between the populations that matching and adjustment were not able to fully account for.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 1,900 hospitals and more than 45,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientist. The two teams came to similar conclusions. Graphics by Brian Olson.

1. US Food and Drug Administration. FDA approves nasal spray influenza vaccine for self- or caregiver-administration. FDA. Published September 20, 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-nasal-spray-influenza-vaccine-self-or-caregiver-administration. Accessed February 26, 2026.
2. AstraZeneca. FLUMIST, the nation’s only nasal spray flu vaccine, now available for home delivery. Published August 15, 2025. https://www.astrazeneca-us.com/media/press-releases/2025/FLUMIST-the-nations-only-nasal-spray-flu-vaccine-now-available-for-home-delivery.html. Accessed February 24, 2026.

First, we studied 2 million patients diagnosed with type 2 diabetes who had a healthcare encounter between January 1, 2017, and October 31, 2024. Patients with type 2 diabetes who were prescribed a GLP-1 were compared to those who have never been on a GLP-1 medication. We accounted for age, sex, BMI, smoking history, chronic steroid usage, and weight change over time.

For patients with type 2 diabetes who maintained a stable weight, GLP-1 use was associated with an 8.7% lower osteoporosis risk compared to patients who did not use a GLP-1, as seen in Figure 1. Among groups that lost more weight, osteoporosis risk rose for those with and without GLP-1s, but the increase in risk was consistently smaller among GLP-1 users. Weight gain was associated with increased osteoporosis risk among those not on a GLP-1, while weight gain was not associated with statistically significant change in osteoporosis risk for those on a GLP-1.

Next, we studied 380,438 patients without diabetes who were prescribed a GLP-1 or other weight loss medication and who had a visit between January 1, 2017, and October 31, 2024. Patients who were prescribed a GLP-1 were compared to those prescribed a different type of weight loss medication. Like the above analysis, we accounted for age, sex, BMI, smoking history, chronic steroid usage, and weight change over time.

Among patients without diabetes, the pattern differed from patients with type 2 diabetes: patients on a GLP-1 who maintained a stable weight had a higher osteoporosis risk relative to those who maintained a stable weight on another weight loss medication (22.0% higher for GLP-1 users). With increasing weight loss, osteoporosis risk increased in both groups, and the GLP-1 risks were generally similar to or higher than the non-GLP-1 weight loss medication risks. Weight gain among patients without diabetes was associated with increased osteoporosis risk in both groups.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 300 million patient records from 1,900 hospitals and more than 42,000 clinics from all 50 U.S. states, Canada, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientists, in collaboration with a researcher from Johns Hopkins. The two teams came to similar conclusions. Graphics by Brian Olson.

1. Paccou J, Compston JE. Bone health in adults with obesity before and after interventions to promote weight loss. Lancet Diabetes Endocrinol. 2024;12(10):748-760. doi:10.1016/S2213-8587(24)00163-3
2. Cai TT, Li HQ, Jiang LL, et al. Effects of GLP-1 Receptor Agonists on Bone Mineral Density in Patients with Type 2 Diabetes Mellitus: A 52-Week Clinical Study. Biomed Res Int. 2021;2021:3361309. Published 2021 Sep 17. doi:10.1155/2021/3361309
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