Effectiveness of non-pharmaceutical interventions in nine fields of activity to decrease SARS-CoV-2 transmission...

Area of Science:

• Epidemiology
• Public Health

Background:

• Investigated the association between activity restriction levels and SARS-CoV-2 transmissibility in Spain.
• Study period: September 15, 2020, to May 9, 2021.

Purpose of the Study:

• To quantify the impact of various restrictions on the transmission of SARS-CoV-2.
• To determine which types of restrictions were most effective in reducing virus spread.

Main Methods:

• Developed a daily stringency index (0-1) for each of Spain's 50 provinces.
• Employed a hierarchical multiplicative model to analyze the relationship between stringency index and weekly SARS-CoV-2 incidence.
• Quantified effects using median coefficients and bootstrap confidence intervals, with a 12-day lag.

Main Results:

• Overall restrictions reduced SARS-CoV-2 transmission by 22% within one week.
• The most impactful restrictions were in culture and leisure (14%), social distancing (13%), indoor restaurants (10%), and indoor sports (6%).
• Model R-squared values indicated approximately 70% of the variance was explained.

Conclusions:

• Increased public health restrictions demonstrably decreased COVID-19 transmission.
• Acknowledged limitations including collinearity between restriction types and the quantification of qualitative measures, necessitating cautious interpretation of specific attributions.