Evaluation of post-COVID symptoms of the SARS-CoV-2 Delta and Omicron variants in children: a prospective study

Prevalence and impact of persistent symptoms following SARS-CoV-2 infection among healthcare workers: A cross-sectional survey in the SIREN cohort

INTRODUCTION

Following SARS-CoV-2 infection, some patients experience a range of long-lasting symptoms, with a specific burden on their lives and ability to work.

AIM

We describe the prevalence and impact of persistent symptoms pre-/post-vaccination in SIREN study participants.

METHODS

A cross-sectional study of SARS-CoV-2 positive participants was carried out within SIREN, a frequently tested UK healthcare worker cohort with vaccination and demographic data available. Participants with a SARS-CoV-2 positive PCR or anti-SARS-CoV-2 sample between 01 March 2020 and 31 September 2022 were asked via a questionnaire about symptoms and days absent from work following infection. Responses were excluded if infection dates were inconsistent with study records or missing key data. Symptom type/duration and whether infection occurred pre-/post-vaccination and during which variant period were described. Logistic regression was used to estimate factors associated with persistent symptoms (>12 weeks), adjusting for vaccination and demographic factors. The median days absent from work were also determined.

RESULTS

Of 16,599 invitations, 6677 participants responded, and 5053 were included in the analysis. The prevalence of persistent symptoms (symptoms lasting over 12 weeks) differed by infection episode; highest for first infections (32.7%; 1557/4767) compared to second (21.6%; 214/991) and third infections (21.6%; 16/74). Most frequently reported symptoms were fatigue, tiredness, shortness of breath and difficulty concentrating. A higher prevalence of persistent symptoms was reported during the Wild-type variant period compared to the other variant periods (52.9% Wild-type vs. 20.7% Omicron, for any symptom reported during their first infection). Overall, persistent symptoms were higher among unvaccinated participants (unvaccinated 38.1% vs vaccinated 22.0%). Multivariable analysis showed that participants were less likely to report persistent symptoms in infections occurring after vaccination compared to those with an infection before vaccination in the Alpha/Delta and Omicron periods (Alpha/Delta: adjusted Odds Ratio (aOR) 0.66, CI 95% 0.51-0.87, p = aOR 0.07, CI 95% 0.01-0.65, p = 0.02). About half of participants reported that their persistent symptoms impacted their day-to-day (51.8%) and work-related (42.1%) activities 'a little', and 24.0% and 14.4% reported that the impact was 'A lot'. 8.9% reported they had reduced their working hours, and 13.9% had changed their working pattern.

DISCUSSION

Persistent symptoms were frequent in our cohort, and there was a reduction in symptom duration in those with multiple infection episodes during later variant periods and post-vaccination. The impact of persistent symptoms resulting in reducing working hours or adjusting working patterns has important implications for workforce resilience. UK healthcare workers were highly exposed during the pandemic, demonstrating a significant burden.

Impact of Long SARS-CoV-2 Omicron Infection on the Health Care Burden: Comparative Case-Control Study Between Omicron and Pre-Omicron Waves

BACKGROUND

Following the initial acute phase of COVID-19, health care resource use has escalated among individuals with SARS-CoV-2 infection.

OBJECTIVE

This study aimed to compare new diagnoses of long COVID and the demand for health services in the general population after the Omicron wave with those observed during the pre-Omicron waves, using similar assessment protocols for both periods and to analyze the influence of vaccination.

METHODS

This matched retrospective case-control study included patients of both sexes diagnosed with acute SARS-CoV-2 infection using reverse transcription polymerase chain reaction or antigen tests in the hospital microbiology laboratory during the pandemic period regardless of whether the patients were hospitalized. We included patients of all ages from 2 health care departments that cover 604,000 subjects. The population was stratified into 2 groups, youths (<18 years) and adults (≥18 years). Patients were followed-up for 6 months after SARS-CoV-2 infection. Previous vaccination, new diagnoses, and the use of health care resources were recorded. Patients were compared with controls selected using a prospective score matched for age, sex, and the Charlson index.

RESULTS

A total of 41,577 patients with a history of prior COVID-19 infection were included, alongside an equivalent number of controls. This cohort encompassed 33,249 (80%) adults aged ≥18 years and 8328 (20%) youths aged <18 years. Our analysis identified 40 new diagnoses during the observation period. The incidence rate per 100 patients over a 6-month period was 27.2 for vaccinated and 25.1 for unvaccinated adults (P=.09), while among youths, the corresponding rates were 25.7 for vaccinated and 36.7 for unvaccinated individuals (P<.001). Overall, the incidence of new diagnoses was notably higher in patients compared to matched controls. Additionally, vaccinated patients exhibited a reduced incidence of new diagnoses, particularly among women (P<.001) and younger patients (P<.001) irrespective of the number of vaccine doses administered and the duration since the last dose. Furthermore, an increase in the use of health care resources was observed in both adult and youth groups, albeit with lower figures noted in vaccinated individuals. In the comparative analysis between the pre-Omicron and Omicron waves, the incidence of new diagnoses was higher in the former; however, distinct patterns of diagnosis were evident. Specifically, depressed mood (P=.03), anosmia (P=.003), hair loss (P<.001), dyspnea (<0.001), chest pain (P=.04), dysmenorrhea (P<.001), myalgia (P=.011), weakness (P<.001), and tachycardia (P=.015) were more common in the pre-Omicron period. Similarly, health care resource use, encompassing primary care, specialist, and emergency services, was more pronounced in the pre-Omicron wave.

CONCLUSIONS

The rise in new diagnoses following SARS-CoV-2 infection warrants attention due to its potential implications for health systems, which may necessitate the allocation of supplementary resources. The absence of vaccination protection presents a challenge to the health care system.

Differences in the Clinical Manifestations and Host Immune Responses to SARS-CoV-2 Variants in Children Compared to Adults

The COVID-19 pandemic challenged the medical field to rapidly identify and implement new approaches to the diagnosis, treatment and prevention of SARS-CoV-2 infections. The scientific community also needed to rapidly initiate basic, translational, clinical and epidemiological studies to understand the pathophysiology of this new family of viruses, which continues to evolve with the emergence of new genetic variants. One of the earliest clinical observations that provided a framework for the research was the finding that, in contrast to most other respiratory viruses, children developed less severe acute and post-acute disease compared to adults. Although the clinical manifestations of SARS-CoV-2 infection changed with each new wave of the pandemic, which was dominated by evolving viral variants, the differences in severity between children and adults persisted. Comparative immunologic studies have shown that children mount a more vigorous local innate response characterized by the activation of interferon pathways and recruitment of innate cells to the mucosa, which may mitigate against the hyperinflammatory adaptive response and systemic cytokine release that likely contributed to more severe outcomes including acute respiratory distress syndrome in adults. In this review, the clinical manifestations and immunologic responses in children during the different waves of COVID-19 are discussed.