COVID-19 Symptoms and Duration of Rapid Antigen Test Positivity at a Community Testing and Surveillance Site During Pre-Delta, Delta, and Omicron BA.1 Periods
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Abstract
Characterizing the clinical symptoms and evolution of community-based SARS-CoV-2 infections may inform health practitioners and public health officials in a rapidly changing landscape of population immunity and viral variants.
Objectives
To compare COVID-19 symptoms among people testing positive with a rapid antigen test (RAT) during the Omicron BA.1 variant period (December 1, 2021, to January 30, 2022) with the pre-Delta (January 10 to May 31, 2021) and Delta (June 1 to November 30, 2021) variant periods and to assess the duration of RAT positivity during the Omicron BA.1 surge.
Design, Setting, and Participants
This cross-sectional study was conducted from January 10, 2021, to January 31, 2022, at a walk-up community COVID-19 testing site in San Francisco, California. Participants included children and adults seeking COVID-19 testing with an RAT, regardless of age, vaccine status, or symptoms.
Main Outcomes and Measures
Fisher exact tests or χ 2 tests were used to compare COVID-19 symptoms during the Omicron BA.1 period with the pre-Delta and Delta periods for vaccination status and age group. Among people returning for repeated testing during the Omicron period, the proportion with a positive RAT between 4 and 14 days from symptom onset or since first positive test if asymptomatic was estimated.
Results
Among 63 277 persons tested (median [IQR] age, 32 [21-44] years, with 12.0% younger than 12 years; 52.0% women; and 68.5% Latinx), a total of 18 301 people (28.9%) reported symptoms, of whom 4565 (24.9%) tested positive for COVID-19. During the Omicron BA.1 period, 3032 of 7283 symptomatic participants (41.6%) tested positive, and the numbers of these reporting cough and sore throat were higher than during pre-Delta and Delta periods (cough: 2044 [67.4%] vs 546 [51.3%] of 1065 participants, P < .001 for pre-Delta, and 281 [60.0%] of 468 participants, P = .002, for Delta; sore throat: 1316 [43.4%] vs 315 [29.6%] of 1065 participants, P < .001 for pre-Delta, and 136 [29.1%] of 468 participants, P < .001, for Delta). Compared with the 1065 patients with positive test results in the pre-Delta period, congestion among the 3032 with positive results during the Omicron BA.1 period was more common (1177 [38.8%] vs 294 [27.6%] participants, P < .001), and loss of taste or smell (160 [5.3%] vs 183 [17.2%] participants, P < .001) and fever (921 [30.4%] vs 369 [34.7%] participants, P = .01) were less common. In addition, during the Omicron BA.1 period, fever was less common among the people with positive test results who had received a vaccine booster compared with those with positive test results who were unvaccinated (97 [22.5%] of 432 vs 42 [36.2%] of 116 participants, P = .003), and fever and myalgia were less common among participants who had received a booster compared with those with positive results who had received only a primary series (fever: 97 [22.5%] of 432 vs 559 [32.8%] of 1705 participants, P < .001; myalgia: 115 [26.6%] of 432 vs 580 [34.0%] of 1705 participants, P = .003). During the Omicron BA.1 period, 5 days after symptom onset, 507 of 1613 people (31.1%) with COVID-19 stated that their symptoms were similar, and 95 people (5.9%) reported worsening symptoms. Among people testing positive, 80.2% of participants who were symptomatic and retested remained positive 5 days after symptom onset.
Conclusions and Relevance
In this cross-sectional study, COVID-19 upper respiratory tract symptoms were more commonly reported during the Omicron BA.1 period than during the pre-Delta and Delta periods, with differences by vaccination status. Rapid antigen test positivity remained high 5 days after symptom onset, supporting guidelines requiring a negative test to inform the length of the isolation period.
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SciScore for 10.1101/2022.05.19.22274968: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: Ethics statement: The study was conducted under a public health surveillance program that was reviewed by the UCSF Committee on Human Research and determined to be exempt and waived from IRB oversight.
Consent: All participants provided informed consent in their preferred language prior to survey administration and COVID-19 testing.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
No key resources detected.
Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We …SciScore for 10.1101/2022.05.19.22274968: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: Ethics statement: The study was conducted under a public health surveillance program that was reviewed by the UCSF Committee on Human Research and determined to be exempt and waived from IRB oversight.
Consent: All participants provided informed consent in their preferred language prior to survey administration and COVID-19 testing.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
No key resources detected.
Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:Our study had certain limitations. Although it was cross-sectional, our data provide an important synthesis of symptomatology within a diverse population of people seeking community testing. Second, symptoms and timing of onset were self-reported which, may introduce bias; however, symptom data were collected prior to persons knowing their COVID-19 test result and thus would not be expected to result in differential bias between those who were COVID-19 positive and negative. Additionally, we did not characterize the severity of COVID-19 symptoms across waves, and even a single very severe symptom can cause substantially greater morbidity in an individual than multiple mild symptoms. Finally, testing was undertaken with rapid antigen tests, and thus may have resulted in misclassification of individuals during the earliest phases of their illness. Nonetheless, strict quality control measures were implemented to ensure accuracy of results and the use of rapid antigen tests. In summary, the clinical presentation of symptomatic persons changed over time during several COVID surges characterized by increasing population immunity and different SARS CoV-2 variants. During Omicron, when population immunity was higher, persons with symptoms often did not see improvement after 5 days and antigen tests frequently remained positive. These findings highlight the importance of work assurances to protect workers and requirements for rapid antigen testing to shorten isolation to protect the w...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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