The road to recovery: an interrupted time series analysis of policy intervention to restore essential health services in Mexico during the COVID-19 pandemic.

Background: Recovery of health services disrupted by the COVID-19 pandemic represents a significant challenge in low- and middle-income countries. In April 2021, the Mexican Institute of Social Security (IMSS), which provides health care to 68.5 million people, launched the National Strategy for Health Services Recovery (Recovery policy). The study objective was to evaluate whether the Recovery policy addressed COVID-related declines in maternal, child health, and non-communicable diseases (NCDs) services. Methods: We analysed the data of 35 IMSS delegations from January 2019 to November 2021 on contraceptive visits, antenatal care consultations, deliveries, caesarean sections, sick children's consultations, child vaccination, breast and cervical cancer screening, diabetes and hypertension consultations, and control. We focused on the period before (April 2020 - March 2021) and during (April 2021 - November 2021) the Recovery policy and used an interrupted time series design and Poisson Generalized Estimating Equation models to estimate the association of this policy with service use and outcomes and change in their trends. Results: Despite the third wave of the pandemic in 2021, service utilization increased in the Recovery period, reaching (at minimum) 49% of pre-pandemic levels for sick children's consultations and (at maximum) 106% of pre-pandemic levels for breast cancer screenings. Evidence for the Recovery policy role was mixed: the policy was associated with increased facility deliveries (IRR = 1.15, 95%CI = 1.11-1.19) with a growing trend over time (IRR = 1.04, 95%CI = 1.03-1.05); antenatal care and child health services saw strong level effects but decrease over time. Additionally, the Recovery policy was associated with diabetes and hypertension control. Services recovery varied across delegations. Conclusions: Health service utilization and NCDs control demonstrated important gains in 2021, but evidence suggests the policy had inconsistent effects across services and decreasing impact over time. Further efforts to strengthen essential health services and ensure consistent recovery across delegations are warranted.