Nina Cosdon

COVID-19 diagnostic tests, once a luxury at the beginning of the pandemic, are thankfully now more accessible in the US. Naso-pharyngeal RT-PCR tests are highly accurate, but for rapid results at home, some opt for rapid lateral flow antigen tests.

The need for inexpensive, reliable, rapid tests is augmented by the relatively large proportion of children who are unvaccinated. One study, presented at this week’s 40th Annual Meeting of the European Society for Pediatric Infectious Diseases (ESPID), assessed the performance of the “COVID-VIRO ALL IN” COVID-19 rapid test in children.

This cross-sectional, prospective, multicenter, real-life study was conducted from September 1, 2021-January 3, 2022. Children 0-15 years old were recruited after presenting to emergency departments and ambulatory settings. The children were either symptomatic for COVID-19 or had been exposed to an infected person.

All children were given a SARS-CoV-2 RT-PCR or rapid antigen test, and a self-test. Above the age of 6, the children could easily perform the self-tests themselves, whereas younger children required the help of a parent or other adult.

The COVID-VIRO ALL IN (AAZ-LMB, Boulogne Billancourt, France) test was used for this study, due to its short sampling device and soft sponge swab. The comfort of use allowed for long sampling (15 seconds per nostril). The investigators compared self-collected nasal swabs to RT-PCR tests, estimating the accuracy and acceptance of these tests for pediatric populations.

A total of 836 pediatric patients, aged an average of 4 years, completed the COVID-19 diagnostic tests. A total of 92.6% of the children were symptomatic, and the prevalence of COVID-19 was 18.4%.

In comparison to the RT-PCR test, the sensitivity of the self-collected nasal swab test was 72.6% during the period when the Delta variant was predominant, and 87.0% during the Omicron wave.

False negative self-tests were largely aligned with low viral loads. Low viral load was established by RT-PCR with a cycle threshold ≥33 and/or a SARS-CoV-2 rapid antigen test positive in more than 3 minutes. The youngest child confirmed positive with a self-test was 1 month old.

On a scale from 1-10, with 1 being “very pleasant” and 10 being “very unpleasant,” 77.9% of children rated the test ≤ 3.

The investigators concluded that the nasal self-test used in this study was reliable, particularly in more contagious children. They noted that it is vital to provide highly accurate tests that are less invasive and unpleasant to encourage families to test their children for COVID-19.

This article originally appeared on ContagionLive.

This study, “Diagnostic Accuracy of SARS-CoV-2 Antigen Detection Self-Test in Children: Vigil Study 3,” was presented during the 

40th Annual Meeting of the European Society for Pediatric Infectious Diseases (ESPID)

, held online and in Athens, Greece from May 9-13, 2022.

Articles

A comparison of COVID-19 PCR tests and rapid self-tests found self-tests to be highly accurate and user-friendly for children.

Self-Tests for COVID-19 Are Accurate and Tolerable for Children

Antibiotic prescriptions increased during COVID-19, forcing us to grapple with the antimicrobial resistance pandemic in addition to the coronavirus pandemic.

Antimicrobial resistance is caused by using excessive, unnecessary antibiotics, allowing dangerous pathogens to learn to mutate and develop resistance to antibiotic therapies. The growing threat of antimicrobial resistance means there will be more and more infections that are unresponsive to even the strongest of antibiotics.

While it is well-documented that antimicrobial consumption increased in adults hospitalized with COVID-19 infection, one study, presented this week at the 40th Annual Meeting of the European Society for Pediatric Infectious Diseases (ESPID), evaluated whether this trend was consistent in pediatric populations.

The study, “Antimicrobial Prescribing in Hospitalized Children with COVID-19,” analyzed the co-infections, prevalence, and characteristics of antibiotic usage in children hospitalized with COVID-19.

This single-center, retrospective study was conducted from March 2020-December 2021. It included children (under 18 years of age) who had a positive RT-PCR SARS-CoV-2 test and were subsequently admitted to a COVID-19 referral pediatric hospital. The investigators reviewed the medical records of children for demographics and clinical characteristics, before collecting data on their antimicrobial consumption.

A total of 299 children with confirmed infection were included in the study. The median patient age was 4 years, and the cohort was 53.3% male. The children were hospitalized for an average of 5 days, and this was also the mean duration of antibiotic use. Antimicrobials were documented in 25% of patients (n = 75), and an average of 1.2 antimicrobials were prescribed per patient.

The most frequently prescribed antibiotics were penicillin (36%), cefotaxime (24%), ampicillin and gentamicin (16%), and macrolides (13.3%). Secondary bacterial infection or co-infection was reported in 26.6% of the children who received antimicrobials.

Among the children with severe COVID-19 disease, 41.3% were prescribed antibiotics for an average of 5 days. Of these children, 58.3% had abnormal chest imaging and 32% had increased C-reactive protein above 60 mg/L.

The antibiotics were either stopped or deescalated within 72 hours in 48% of patients (n = 36), without backing clinical, laboratory, or radiological evidence of bacterial infection, and 29.3% (n = 22) were neonates with fever.

The investigators concluded that of the 25% of hospitalized children prescribed antibiotics for COVID-19 infection, most received narrow spectrum antibiotics. They recommended that hospitals should determine and apply diagnostic criteria to avoid overprescribing antibodies for COVID-19.

This study, “Antimicrobial Prescribing in Hospitalized Children with COVID-19,” was presented during the 40th Annual Meeting of the European Society for Pediatric Infectious Diseases (ESPID), held online and in Athens, Greece from May 9-13, 2022.

A session at the 40th Annual Meeting of the European Society for Pediatric Infectious Diseases looks at how the pandemic impacted the used of antimicrobials.

Examining Antimicrobial Use in Children Hospitalized with COVID-19

Though slightly less accurate than the genetic COVID-19 tests administered in healthcare settings, rapid antigen tests have allowed people to test for COVID-19 quickly and cheaply from home.

However, rapid antigen tests were developed and authorized using the original strain of SARS-CoV-2 that emerged in 2019. Since then, there have been several highly infectious mutations of the virus, such as the Delta and Omicron variants.

 hypothesized that the rapid tests may be less effective in detecting the emerging “variants of concern.”

The most recent variants of concern, Delta and Omicron, contain numerous amino acid mutations to the spike protein. Additionally, Delta has D63G, R203M, and D377Y nucleocapsid mutations, while Omicron has P13L, Δ31–33, R203K, and G204R nucleocapsid mutations.

The easy-to-use rapid antigen COVID-19 tests differ from sensitive molecular tests in that they do not detect multiple genes, but rather 1 genetically conserved nucleocapsid viral protein. The investigators noted that most of the rapid tests approved under Emergency Use Authorization (EUA) by the US Food and Drug Administration (FDA) feature limits of detection (LoDs) established with gamma-irradiated or heat-inactivated preparations of the USA WA1/2020 (WA1) strain, lacking the Delta and Omicron nucleocapsid mutations.

The investigators used cultured plaque-titered live Omicron, Delta, and WA1 COVID-19 strains to assess differences in the LoDs of 4 different rapid antigen tests. Using LoD, the smallest amount of viral antigen detectable with 95% certainty, they analyzed the Binax, CareStart, GenBody, and LumiraDx tests.

The study found that all tests were highly sensitive to the Omicron variant, with a 95% LoD threshold either equivocal to or lower than the original WA1 strain. However, LoDs for Delta were 40- to 140-fold higher than for WA1 in all tests but the CareStart.

“We expect that the observed loss in Delta sensitivity could have resulted in a 20% or more loss of detection in potentially infectious individuals,” said James Kirby, MD, a study author and director of the Clinical Microbiology Laboratory at the Beth Israel Deaconess Medical Center. He then pointed out, “Nevertheless, the most infectious individuals still should have been detected.”

This “true reduction in analytical sensitivity for Delta” could have implications of decreased test accuracy for any emerging or future variants of concern.

“Our findings suggest that antigen test performance needs to be reevaluated for emerging variants to ensure they still meet the intended public health testing goals of the pandemic,” Kirby said.

Stanley S, Hamel DJ, Wolf ID, et al. Limit of Detection for Rapid Antigen Testing of the SARS-CoV-2 Omicron and Delta Variants of Concern Using Live-Virus Culture. 

. 2022 Apr 20;e0014022. doi: 10.1128/jcm.00140-22. Online ahead of print.

Investigators examined whether rapid antigen tests were less sensitive to variants of concern. Though the tests detected Omicron, all but 1 were less effective in detecting the Delta variant.