RESUMO
BACKGROUND: After the establishment of the public health emergency of international concern in 2020, health systems worldwide and in Brazil observed the need to apply more extraordinary logistical efforts and possibly resources to combat the imminent pandemic. METHODS: Using the historical series of public expenditures of the National Health Fund (FNS), 2015 to 2021, the number of confirmed cases of COVID-19, and a seasonal ARIMAX model, we sought to assess how the increase in the new virus infections affected the systematic financing of the SUS in Brazil. RESULTS: There were signs of seasonality and an increasing trend in the expenditure variable, which in practical terms, only indicated that the resource contributions followed an increasing trajectory already underway before the advent of the pandemic. The 1% increase in COVID-19 cases, with a one-month lag, contributes to the 0.062% increase in the variation in FNS expenditures but a decrease of 0.058% with a two-month lag. CONCLUSION: The tests showed no evidence to confirm a positive shift on FNS spending growth trajectory due to the increase of COVID-19 cases, only observing a significant increase one month after the occurrence of COVID cases, probably due to their worsening after this period, which was followed by a similar and comparable decrease in percentage of growth in the following month.