Evaluating a SARS-CoV-2 screening strategy based on serological tests.

Area of Science:

• Epidemiology
• Infectious Disease Modeling
• Public Health Strategies

Background:

• The SARS-CoV-2 pandemic necessitates widespread testing for early identification and isolation of infected individuals.
• While RT-PCR is the gold standard for detecting active infections, serological tests are often considered for broad screening.
• Evaluating the efficacy of combined testing strategies is crucial for pandemic management.

Purpose of the Study:

• To analyze the performance of a proposed screening strategy combining qualitative rapid antibody tests with RT-PCR for SARS-CoV-2 detection.
• To estimate the number of RT-PCR tests required and the rate of undetected infections under various prevalence scenarios.

Main Methods:

• A simulation study was conducted on a pseudo-population of 500,000 subjects.
• The strategy involved initial rapid antibody testing followed by RT-PCR for positive cases.
• A compartmental model predicted new infections from false negatives, considering different reproduction numbers and serological test sensitivities (0.50-0.80) and specificity (0.98).

Main Results:

• With 0.80 sensitivity and 0.3% prevalence, the strategy required ~11,167 RT-PCR tests and yielded 300 false negatives.
• These false negatives could cause 526-1,132 new infections within two months (reproduction number 0.5-1).
• Increased prevalence led to higher resource demands and more false negatives.

Conclusions:

• The analyzed screening strategy is not recommended unless SARS-CoV-2 prevalence and contagion rates are very low.
• The cost-effectiveness of any screening strategy must be context-specific and adaptable to epidemic dynamics.
• Careful evaluation of screening protocols is essential to balance resource allocation and public health outcomes.