JMIR Publications

ABSTRACT

Background:

Early detection and isolation are key strategies for containing the COVID 19 pandemic in resource-poor contexts, including Afghanistan, where access to the vaccines is limited. These strategies could reduce the burden on the health care system which is already weak due to conflicts and war. Both RT-PCR. The first COVID 19 case was detected in the country in Herat province close to Iran. Currently, rapid antigen tests and RT-PCR have been used for detections of COVID 19 cases in the Herat province. The aim of this study is to assess the accuracy of the rapid antigen test among asymptomatic close contacts of individuals confirmed for COVID 19 in the Herat province.

Methods:

This was a cross-sectional study conducted by the surveillance contact tracing teams in Herat province. The teams line listed 200 asymptomatic close contacts, and two separate nasopharyngeal specimens were collected. We used the rapid antigen test (Biosensor) on the 4th-7th days of the contact, and the 2nd specimen was sent to the reference lab for RT-PCR testing. Descriptive statistics were conducted. The sensitivity and specificity of the rapid antigen tests were compared with RT-PCR test results.

Results:

The median age of the contacts was 35 years (ranged 11-90), and 138(70%) of the contacts were female. Out of 196 contacts tested with the RT-PCR, 105(53%) were confirmed for SARS-COV-2 infection, while only 30(15%) were confirmed by rapid antigen test. It indicates a sensitivity of 20.1%. However, the specificity of the rapid antigen test was high (90%).

Conclusions:

The sensitivity of the rapid antigen tests was quite low to confirm covid 19 cases among asymptomatic close contacts. Therefore, if resources allow, RT-PCR is still the best choice with a high sensitivity rate for early detection of the covid 19 asymptomatic close contacts. Further study with a large sample size should be considered.