Older Adults Often Delay ED Visits for Suspected Fever After COVID-19 Vaccination

Close up of Vials and Syringes with Covid-19 vaccine are displayed on a tray during vaccination.
Researchers assessed the clinical features of older vs younger adults who visited the emergency department for suspected fever after COVID-19 vaccination.

Among adult patients who presented to the ED for suspected fever after COVID-19 vaccination, those who were older were less likely to have fever on ED admission and were more likely to delay their ED visit and require subsequent hospitalization for conditions unrelated to vaccination. These results were published in a study in the Journal of Infection and Chemotherapy

In this retrospective observational study conducted between March and September 2021, researchers analyzed the clinical features of older vs younger adults who visited an ED with self-reported fever following COVID-19 vaccination. The researchers considered older patients as those aged 65 years and older and younger patients as those between 19 and 64 years. Patients who reported symptoms more than 2 weeks after vaccination were excluded.

A total of 562 patients were included in the final analysis, of whom 396 (70.5%) were women, 155 (27.6%) were aged 65 years and older, and most (>63.9%) were admitted to an ED after receipt of the first COVID-19 vaccine dose.

The rate of fever was decreased among older vs younger patients on ED admission (75.5% vs 85.7%; P =.004), and older patients were more likely to require use of emergency medical services (43.9% vs 18.7%; P <.001). 

Although the time of symptom onset following vaccination was similar between older and younger patients, older patients were significantly more likely to delay a visit to the ED (P =.004). In addition, overall admissions (32.9% vs 4.2%), intensive care unit admissions (7.1% vs 1.0%), and median length of ED stay (3.5 vs 2.0 hours) were increased among older vs younger patients (all P <.001). Older patients who were admitted were most commonly diagnosed with urinary tract infection (27.5%), pneumonia (23.5%), hepatobiliary infection (15.7%), and gastrointestinal infection (13.7%). 

A total of 86 (83.5%) older patients received a discharge diagnosis of an adverse reaction related to COVID-19 vaccination.

The study was limited by its small sample size, retrospective design, and potential selection bias. Other limitations were the use of different types of COVID-19 vaccines, and the short follow-up duration.

According to the researchers, “emergency [medicine] physicians should consider not only adverse reactions but also other infectious diseases in febrile older adults visiting the ED after COVID-19 vaccination.”


Jeong S, Hong S, Oh T, et al. Analysis of older adults visiting the emergency department with fever as a suspected Covid-19 vaccine-related adverse reaction: A retrospective multicenter study. J Infect Chemother. Published online May 2, 2022. doi:10.1016/j.jiac.2022.04.022

This article originally appeared on Infectious Disease Advisor