All Articles

Most COVID-19 hospitalization statistics include all patients who are admitted to the hospital with a COVID-19 diagnosis or COVID-19 positive lab test. However, it’s possible for patients to test positive for COVID-19 while admitted for an unrelated problem, such as a head injury or a heart attack, and experience a mild or asymptomatic case of COVID-19 that might not require hospitalization on its own. Some studies and recent media reports suggest that this might lead experts to overcount COVID-19-related admissions, especially for children.

Infants less than two months old are most likely to be hospitalized with a COVID infection compared to other children under five years old. Hospitalizations were highest during the period where the Delta variant was prominent for all age groups under five years old.

Pediatric suicide and self-harm attempts are on the rise, especially for 13- to 15-year-olds and females. Universal screenings, patient safety plans, and provider facilitation of family communication can help address the mental health concerns that have led to this increase. Suicide is the second leading cause of death in the U.S. for 10- to 17-year-olds, and the youth suicide rate increased 56% between 2007 and 2017. Our data show that this trend has continued through 2021 as pediatric suicide and self-harm encounters in the emergency department and hospital increased for all age groups.

Previous infection with SARS-CoV-2, the virus that causes COVID-19, has been estimated to confer up to 90% protection against reinfection, although this protection was lower against the Omicron variant compared with that against other SARS-CoV-2 variants. A test-negative design was used to estimate effectiveness of COVID-19 mRNA vaccines in preventing subsequent COVID-19–associated hospitalization among adults aged ≥18 years with a previous positive nucleic acid amplification test (NAAT) or diagnosis of COVID-19. The analysis used data from Cosmos, an electronic health record (EHR)–aggregated data set, and compared vaccination status of 3,761 case-patients (positive NAAT result associated with hospitalization) with 7,522 matched control-patients (negative NAAT result). After previous SARS-CoV-2 infection, estimated vaccine effectiveness (VE) against COVID-19–associated hospitalization was 47.5% (95% CI = 38.8%–54.9%) after 2 vaccine doses and 57.8% (95% CI = 32.1%–73.8%) after a booster dose during the Delta-predominant period (June 20–December 18, 2021), and 34.6% (95% CI = 25.5%–42.5%) after 2 doses and 67.6% (95% CI = 61.4%–72.8%) after a booster dose during the Omicron-predominant period (December 19, 2021–February 24, 2022). Vaccination provides protection against COVID-19–associated hospitalization among adults with previous SARS-CoV-2 infection, with the highest level of protection conferred by a booster dose. All eligible persons, including those with previous SARS-CoV-2 infection, should stay up to date with vaccination to prevent COVID-19–associated hospitalization. 

A large body of previous research has demonstrated racial gaps in autism diagnosis, with White children diagnosed with autism spectrum disorder (ASD) earlier and more often than children in other racial and ethnic groups. More recent analyses, such as those by the CDC, have found that those gaps are declining. In our analysis, we found further evidence that efforts to reach parity across rates of diagnosis and age of diagnosis have been successful as those differences are declining across all racial groups.

Underlying medical conditions associated with high risk for severe COVID-19 are outlined by the CDC. In this study, we quantify how certain comorbidities could affect the risk of a breakthrough COVID-19 case, defined as getting a COVID-19 infection after being fully vaccinated.

Like healthcare visit volumes in the outpatient space, emergency department (ED) visit volumes dropped significantly at the beginning of the pandemic and had not yet recovered as of early 2021.1 While weekly ED visit volume has increased, volumes declined again to 12% fewer visits than expected as the pandemic continued through the remainder of 2021, as shown in Figure 1. These decreased volumes, however, don’t mean less work for ED physicians, nurses, and caregivers.

Since the start of the pandemic, hospitals have been experiencing capacity issues as COVID-19 infections requiring hospitalization have taken hold. As shown in Figure 1, we identified five distinct surges in COVID hospitalizations across the U.S. between March 2020 and November 2021. In each surge, daily admissions increased at least 10% from the previous average weekly admissions.

Throughout the pandemic, some people have been reluctant to go to the hospital or ED due to concerns about contracting COVID. We wanted to investigate the frequency with which patients developed COVID-19 while hospitalized. As a proxy for this, we looked at patients who tested negative on the day of or day after admission and then tested positive six or more days later.2 We chose this timeframe to try to exclude patients who might have been positive on admission but tested negative at that time due to a lower viral load.

While pediatric hospitalization rates for COVID-19 remain much lower than adult hospitalization rates for the same conditions, less is known about the differences in hospitalization rates for COVID-vaccinated and unvaccinated pediatric patients. Additionally, we sought to understand whether COVID vaccination was associated with hospitalizations for multi-system inflammatory syndrome in children (MIS-C), a serious condition associated with COVID-19.

Recent reports have indicated that adolescents and young adults, particularly males ages 12-29, who receive an mRNA COVID-19 vaccine have an increased risk of myocarditis, an inflammation of the heart muscle. In October 2021, the FDA delayed its decision on the authorization of the Moderna vaccine for adolescents due to these concerns. We previously studied the risk of myocarditis across 15 million patients of all ages and found that the incidence of myocarditis following the COVID-19 vaccine was not substantively different from the incidence in pre-pandemic years.

Routine cancer screenings are a primary preventative care measure that decreased dramatically at the start of the pandemic with 94% decreases in both breast cancer screenings and cervical cancer screenings and an 86% decrease in colon cancer screenings. While cancer screening rates rebounded in 2021 from early pandemic lows, they were still lower than expected.

Guillain-Barré Syndrome (GBS) is a rare autoimmune disorder in which a person’s nerves are damaged, causing muscle weakness and sometimes paralysis. Patients can sometimes develop GBS after having a recent respiratory illness or digestive tract infection, and in rare cases, after receiving certain vaccines.

Since the beginning of the COVID-19 pandemic, hospital capacity has been a consistent concern. People who are fully vaccinated against COVID-19 have a significantly reduced risk of severe illness resulting in hospitalization,1,2 which can help reduce the impact of COVID-19 on hospital capacity.

To examine how vaccines affect immunity for people who have already had COVID-19, we compared reinfection rates of COVID-19 in vaccinated and unvaccinated patients and found that unvaccinated patients were significantly more likely to be reinfected. To best determine whether a patient was vaccinated or unvaccinated, our study population included those with a face-to-face encounter where vaccination status could be verified.

We studied how vaccine availability and the emergence of variants of COVID-19 have affected different age groups of patients hospitalized with COVID-19. The data show that the distribution of COVID hospitalizations among different age groups has remained relatively stable since the start of the pandemic. However, there are two noteworthy trends:

A pregnant patient’s body mass index (BMI) can affect the risk of complications for both the patient and the baby.1 We reviewed EHR data for more than 900,000 pregnancies that had pre-pregnancy BMI data to identify rates of certain delivery, prenatal, and postpartum complications.  Figure 1 shows rates of cesarean section, preterm delivery, and low birth weight. Rates of cesarean section increase steadily as maternal BMI increases, while rates of preterm delivery and […]

Many other healthcare settings have seen changes in the patient populations they see since the beginning of the COVID-19 pandemic. Prior to the pandemic, urgent care facilities were becoming popular alternatives to emergency departments for patients with urgent, but non-life-threatening, conditions. We wondered how the pandemic has impacted the volume and types of care sought in urgent care since many patients with respiratory symptoms may not need emergency care.

A commentary on this article was also published in NEJM Catalyst. Even for experienced clinicians, distinguishing between sore throats of viral and bacterial origin by observation alone is particularly challenging. Before most patients with a sore throat are prescribed antibiotics, the American Academy of Family Physicians recommends a positive diagnostic test for group A beta-hemolytic streptococci (GABHS). Empiric antibiotics, or antibiotics without a test, should be limited because they aren’t effective for viral infections and because unneeded antibiotics can cause side effects and antibiotic resistance.

In May and June 2021, we reported that RSV and seasonal influenza cases dropped during the COVID-19 pandemic.  Respiratory viruses other than COVID, like RSV and Influenza, were purported to increase again after measures like masking and social distancing were relaxed in the summer of 2021. EHR data for positive RSV and influenza tests show that the number of RSV cases has risen sharply since May 2021 while the number of influenza cases remains uncharacteristically low.