Streptococcus pneumoniae colonization associates with impaired adaptive immune responses against SARS-CoV-2.

BackgroundAlthough recent epidemiological data suggest that pneumococci may contribute to the risk of SARS-CoV-2 disease, cases of coinfection with Streptococcus pneumoniae in patients with coronavirus disease 2019 (COVID-19) during hospitalization have been reported infrequently. This apparent contradiction may be explained by interactions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and pneumococci in the upper airway, resulting in the escape of SARS-CoV-2 from protective host immune responses.MethodsHere, we investigated the relationship of these 2 respiratory pathogens in 2 distinct cohorts of health care workers with asymptomatic or mildly symptomatic SARS-CoV-2 infection identified by systematic screening and patients with moderate to severe disease who presented to the hospital. We assessed the effect of coinfection on host antibody, cellular, and inflammatory responses to the virus.ResultsIn both cohorts, pneumococcal colonization was associated with diminished antiviral immune responses, which primarily affected mucosal IgA levels among individuals with mild or asymptomatic infection and cellular memory responses in infected patients.ConclusionOur findings suggest that S. pneumoniae impair host immunity to SARS-CoV-2 and raise the question of whether pneumococcal carriage also enables immune escape of other respiratory viruses and facilitates reinfection.Trial registrationISRCTN89159899 (FASTER study) and ClinicalTrials.gov NCT03502291 (LAIV study).

Twelve lateral flow immunoassays (LFAs) to detect SARS-CoV-2 antibodies.

BACKGROUND: There are an abundance of commercially available lateral flow assays (LFAs) that detect antibodies to SARS-CoV-2. Whilst these are usually evaluated by the manufacturer, externally performed diagnostic accuracy studies to assess performance are essential. Herein we present an evaluation of 12 LFAs. METHODS: Sera from 100 SARS-CoV-2 reverse-transcriptase polymerase chain reaction (RT-PCR) positive participants were recruited through the FASTER study. A total of 105 pre-pandemic sera from participants with other infections were included as negative samples. RESULTS: At presentation sensitivity against RT-PCR ranged from 37.4 to 79% for IgM/IgG, 30.3-74% for IgG, and 21.2-67% for IgM. Sensitivity for IgM/IgG improved ≥ 21 days post symptom onset for 10/12 tests. Specificity ranged from 74.3 to 99.1% for IgM/IgG, 82.9-100% for IgG, and 75.2-98% for IgM. Compared to the EuroImmun IgG enzyme-linked immunosorbent assay (ELISA), sensitivity and specificity ranged from 44.6 to 95.4% and 85.4-100%, respectively. CONCLUSION: There are many LFAs available with varied sensitivity and specificity. Understanding the diagnostic accuracy of these tests will be vital as we come to rely more on the antibody status of a person moving forward, and as such manufacturer-independent evaluations are crucial.

Saliva Alternative to Upper Respiratory Swabs for SARS-CoV-2 Diagnosis.

PCR of upper respiratory specimens is the diagnostic standard for severe acute respiratory syndrome coronavirus 2 infection. However, saliva sampling is an easy alternative to nasal and throat swabbing. We found similar viral loads in saliva samples and in nasal and throat swab samples from 110 patients with coronavirus disease.