Antigen-based tests for SARS-CoV-2, the virus that causes coronavirus disease 2019 , are inexpensive and can return results within 15 minutes (1). Antigen tests have received Food and Drug Administration (FDA) Emergency Use Authorization (EUA) for use in asymptomatic and symptomatic persons within the first 5-12 days after symptom onset (2). These tests have been used at U.S. colleges and universities and other congregate settings (e.g., nursing homes and correctional and detention facilities), where serial testing of asymptomatic persons might facilitate early case identification (3-5). However, test performance data from symptomatic and asymptomatic persons are limited. This investigation evaluated performance of the Sofia SARS Antigen Fluorescent Immunoassay (FIA) (Quidel Corporation) compared with real-time reverse transcription-polymerase chain reaction (RT-PCR) for SARS-CoV-2 detection among asymptomatic and symptomatic persons at two universities in Wisconsin. During September 28-October 9, a total of 1,098 paired nasal swabs were tested using the Sofia SARS Antigen FIA and real-time RT-PCR. Virus culture was attempted on all antigenpositive or real-time RT-PCR-positive specimens. Among 871 (79%) paired swabs from asymptomatic participants, the antigen test sensitivity was 41.2%, specificity was 98.4%, and in this population the estimated positive predictive value (PPV) was 33.3%, and negative predictive value (NPV) was 98.8%. Antigen test performance was improved among 227 (21%) paired swabs from participants who reported one or more symptoms at specimen collection (sensitivity = 80.0%; specificity = 98.9%; PPV = 94.1%; NPV = 95.9%). Virus was isolated from 34 (46.6%) of 73 antigen-positive or real-time RT-PCR-positive nasal swab specimens, including two of 18 that were antigen-negative and real-time RT-PCR-positive (false-negatives). The advantages of antigen tests such as low cost and rapid turnaround might allow for rapid identification of infectious persons. However, these advantages need to be
Background
In April 2012, the Jordan Ministry of Health investigated an outbreak of lower respiratory illnesses at a hospital in Jordan; 2 fatal cases were retrospectively confirmed by real-time reverse transcription polymerase chain reaction (rRT-PCR) to be the first detected cases of Middle East respiratory syndrome (MERS-CoV).
Methods
Epidemiologic and clinical characteristics of selected potential cases were assessed through serum blood specimens, medical record reviews, and interviews with surviving outbreak members, household contacts, and healthcare personnel. Cases of MERS-CoV infection were identified using 3 US Centers for Disease Control and Prevention serologic tests for detection of anti–MERS-CoV antibodies.
Results
Specimens and interviews were obtained from 124 subjects. Seven previously unconfirmed individuals tested positive for anti–MERS-CoV antibodies by at least 2 of 3 serologic tests, in addition to 2 fatal cases identified by rRT-PCR. The case-fatality rate among the 9 total cases was 22%. Six subjects were healthcare workers at the outbreak hospital, yielding an attack rate of 10% among potentially exposed outbreak hospital personnel. There was no evidence of MERS-CoV transmission at 2 transfer hospitals having acceptable infection control practices.
Conclusions
Novel serologic tests allowed for the detection of otherwise unrecognized cases of MERS-CoV infection among contacts in a Jordanian hospital-associated respiratory illness outbreak in April 2012, resulting in a total of 9 test-positive cases. Serologic results suggest that further spread of this outbreak to transfer hospitals did not occur. Most subjects had no major, underlying medical conditions; none were on hemodialysis. Our observed case-fatality rate was lower than has been reported from outbreaks elsewhere.
To determine how long antibodies against Middle East respiratory syndrome coronavirus persist, we measured long-term antibody responses among persons serologically positive or indeterminate after a 2012 outbreak in Jordan. Antibodies, including neutralizing antibodies, were detectable in 6 (86%) of 7 persons for at least 34 months after the outbreak.
Because the G protein of respiratory syncytial virus (RSV) has a CX3C chemokine motif that has been associated with the ability of RSV G protein to modulate the virus-induced host immune response, we examined whether therapeutic treatment with an anti-RSV G monoclonal antibody (mAb), 131-2G, that blocks the CX3C-associated activity of RSV G protein might decrease the pulmonary inflammation associated with infection in BALB/c mice. The results show that treatment with mAb 131-2G on day 3 after RSV infection reduces both inflammation and RSV titer in the lungs. Later administration of anti-RSV G mAb (day 5 after RSV infection) effectively reduced the viral titer but had a minimal effect on pulmonary inflammation. This study suggests that an anti-RSV G mAb might be an effective antiviral, either alone or in combination with anti-RSV F protein neutralizing antibodies, for decreasing the virus-induced host response to infection and improve treatment outcome.
We conducted an epidemiologic investigation among survivors of an outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in Jordan. A second-trimester stillbirth occurred during the course of an acute respiratory illness that was attributed to MERS-CoV on the basis of exposure history and positive results of MERS-CoV serologic testing. This is the first occurrence of stillbirth during an infection with MERS-CoV and may have bearing upon the surveillance and management of pregnant women in settings of unexplained respiratory illness potentially due to MERS-CoV. Future prospective investigations of MERS-CoV should ascertain pregnancy status and obtain further pregnancy-related data, including biological specimens for confirmatory testing.
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