Test positivity - Evaluation of a new metric to assess epidemic dispersal mediated by non-symptomatic cases.
Methods
; 195: 15-22, 2021 11.
Article
in English
| MEDLINE | ID: covidwho-1243244
ABSTRACT
Epidemic control may be hampered when the percentage of asymptomatic cases is high. Seeking remedies for this problem, test positivity was explored between the first 60 to 90 epidemic days in six countries that reported their first COVID-19 case between February and March 2020 Argentina, Bolivia, Chile, Cuba, Mexico, and Uruguay. Test positivity (TP) is the percentage of test-positive individuals reported on a given day out of all individuals tested the same day. To generate both country-specific and multi-country information, this study was implemented in two stages. First, the epidemiologic data of the country infected last (Uruguay) were analyzed. If at least one TP-related analysis yielded a statistically significant relationship, later assessments would investigate the six countries. The Uruguayan data indicated (i) a positive correlation between daily TP and daily new cases (râ¯=â¯0.75); (ii) a negative correlation between TP and the number of tests conducted per million inhabitants (TPMI, râ¯=â¯-0.66); and (iii) three temporal stages, which differed from one another in both TP and TPMI medians (pâ¯<â¯0.01) and, together, revealed a negative relationship between TPMI and TP. No significant relationship was found between TP and the number of active or recovered patients. The six countries showed a positive correlation between TP and the number of deaths/million inhabitants (DMI, râ¯=â¯0.65, pâ¯<â¯0.01). With one exception -a country where isolation was not pursued-, all countries showed a negative correlation between TP and TPMI (râ¯=â¯0.74). The temporal analysis of country-specific policies revealed four patterns, characterized by (1) low TPMI and high DMI, (2) high TPMI and low DMI; (3) an intermediate pattern, and (4) high TPMI and high DMI. Findings support the hypothesis that test positivity may guide epidemiologic policy-making, provided that policy-related factors are considered and high-resolution geographical data are utilized.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Asymptomatic Infections
/
COVID-19 Testing
/
COVID-19
Type of study:
Diagnostic study
/
Experimental Studies
/
Observational study
Limits:
Humans
Country/Region as subject:
South America
/
Argentina
/
Bolivia
/
Caribbean
/
Chile
/
Cuba
/
Mexico
/
Uruguay
Language:
English
Journal:
Methods
Journal subject:
Biochemistry
Year:
2021
Document Type:
Article
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