Effective bubble-based testing for SARS-CoV-2 using swab-pooling

Area of Science:

• Virology
• Molecular Biology
• Public Health

Background:

• COVID-19 containment is challenged by vaccine limitations and viral evolution.
• Effective strategies for identifying SARS-CoV-2 carriers are crucial.
• Current testing methods face limitations in scalability and cost-efficiency.

Purpose of the Study:

• To develop and evaluate a scalable and cost-effective PCR testing strategy for SARS-CoV-2.
• To identify carriers of SARS-CoV-2 in a community setting through pooled testing.

Main Methods:

• A bubble-based PCR testing approach was developed, involving swab-pooling into lysis buffer.
• Individuals were grouped into 'bubbles' for periodic, pooled SARS-CoV-2 testing.
• Positive pools triggered individual testing for carrier identification and contact tracing.

Main Results:

• The study tested 25,831 individuals across 1273 bubbles (average size 20.3 swabs/tube).
• Pooled testing (≤37 swabs/pool) achieved 97.5% specificity and 86.3% sensitivity.
• Pooled testing with ≤25 swabs showed improved sensitivity (94.6%) and specificity (97.2%) compared to individual testing.

Conclusions:

• The bubble-based PCR approach significantly scales up testing throughput and reduces costs.
• This method maintains sensitivity and integrates with standard PCR laboratory routines.
• Applicable in various settings like schools and workplaces, it offers a viable strategy for future pandemics.