Objective
Contact tracing aids epidemic control by enabling early detection and isolation without
overburdening healthcare systems despite potential challenges. This study aimed to
evaluate the practical application of contact and risk assessment-based models in
predicting SARS-CoV-2 infection following exposure among healthcare workers in a large
tertiary public university hospital in Türkiye.
Materials and Methods
The study was designed as a retrospective cohort study, including contact tracing data
from 3389 exposed healthcare workers from March 23, 2020, to October 22, 2021.
Contact-based (mask use, contact duration and distance) and exposure
risk-assessment-based (low, medium, high-risk) models with and without having symptoms
were generated using logistic regression. SARS-CoV-2 infection was defined as having a
positive SARS-CoV-2 RT-PCR test result. Adjustments were made to the models for
demographic and occupational variables, previous infection, and vaccination. Model
parameters were compared.
Results
Of 3389 exposed healthcare workers, 2451 underwent RT-PCR testing. Among those tested,
RT-PCR positivity was 5.9% (144/2451). Lack of personal protective equipment use (odds
ratio [OR]=1.64, 95% confidence interval [CI]=1.03-2.66) and ≥15 minutes of contact
duration (1.89, 1.21-3.09) were significantly associated with RT-PCR positivity. In the
risk-assessment model, being a high-risk contact increased the odds of RT-PCR positivity
(OR=2.76, 95% CI=1.61-5.03). Adding the presence of symptoms to contact-based and risk
assessment models improved model parameters (Akaike information criterion [AIC]: from
1086.1 to 1083.1; Tjur's R
2
: from 0.016 to 0.019, respectively).
Conclusion
The inclusion of being symptomatic improved the contact-based and risk assessment-based
models. Institutions should be encouraged to incorporate symptom inquiries into risk
assessment protocols in response to newly emerging respiratory virus epidemics.
Institutions lacking the capacity for extensive contact tracing are recommended, at
minimum, to track symptomatic exposed workers for epidemic control.