Clinical trial NCT04745533: COVID-19 Contact Study by Antigen Detection Test
Official title: Diagnostic Efficacy of the SARS-CoV2 Antigen Detection Test for the COVID-19 Contact Study
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: SARS-CoV Infection
Keywords: Antigen detection tests
Diagnostic efficacy
Contact study
Asymptomatic contacts
Lead sponsor: University of Extremadura
Sponsor class: OTHER
First posted: 2021-02-09
Enrollment: 3000
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: All subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health of Spain in the health area of Cáceres

Brief summary: Stopping the SARS-CoV2 spread is essential to control the pandemic cause by this virus.

A great effort is being made to carry out surveillance, case detection and contact control protocols in order to detect and isolate those contagious subjects.

Since both symptomatic and asymptomatic subjects can be contagious, a surveillance system based on the presence of symptoms is not enough, requiring to perform diagnostic tests in a large number of subjects, such as asymptomatic contacts or high-prevalence populations, and repeatedly. Moreover, the speed in obtaining results is crucial in order not to delay the isolations of positive subjects.

The polymerase chain reaction (PCR) is an expensive test which requires specialized equipment and personnel with a delay in results of 24-48 hours. In addition, its high sensitivity can mean that subjects without infective capacity have a positive result.

In contrast, antigen detection tests (ADTs) are cheap and easy to perform, having a result in few minutes. They have shown high sensitivity and specificity in symptomatic subjects, specially in the first week of symptoms when the viral load is high. This could be very useful for the study of asymptomatic contacts to detect those with potential contagiousness quick, easily and cheaply. However, there is no evidence to support the use of ADTs in this group of subjects.

For this reason, the investigators propose to carry out a study to compare the diagnostic efficacy of ADTs versus PCR in the group of subjects considered to be close contacts of SARS-Cov2 positive patients in the health area of Cáceres.


Eligibility criteria: Inclusion Criteria:

* Subjects considered close contacts of COVID-19 patients according to the definition of the Ministry of Health of Spain at the time of inclusion.

Exclusion Criteria:

* Subjects who do not obtain their informed consent for the study.
* Symptomatic subject at the time of inclusion.

Primary outcomes:
measure: Sensitivity of the antigen detection test used in the study of contacts of COVID-19 patients.
timeFrame: 2 days
measure: Specificity of the antigen detection test used in the study of contacts of COVID-19 patients.
timeFrame: 2 days
Secondary outcomes:
measure: Positive predictive value of the antigen detection test used in the study of contacts of COVID-19 patients.
timeFrame: 2 days
measure: Negative predictive value of the antigen detection test used in the study of contacts of COVID-19 patients.
timeFrame: 2 days
measure: Positive likelihood ratio of the antigen detection test used in the study of contacts of COVID-19 patients.
timeFrame: 2 days
measure: Negative likelihood ratio of the antigen detection test used in the study of contacts of COVID-19 patients.
timeFrame: 2 days
measure: Change in the pretest probability when the antigen detection test result is positive in a COVID-19 patient contact.
timeFrame: 2 days
measure: Change in the pretest probability when the antigen detection test result is negative in a COVID-19 patient contact.
timeFrame: 2 days
measure: Cut-off point of the cycle threshold of the polymerase chain reaction test that discriminates infectivity.
timeFrame: 2 weeks
measure: Risk of SARS-CoV2 infection in close contacts of COVID-19 patients with a positive polymerase chain reaction test depending on whether the antigen detection test is positive or negative.
timeFrame: 2 weeks
measure: To predict a positive result of the polymerase chain reaction test based on the appearance of symptoms during quarantine
timeFrame: 10 days
measure: The percentage of COVID-19 patient contacts with symptoms during the quarantine.
timeFrame: 10 days
Other outcomes:
Locations:
Study officials:
References: