Background
The COVID-19 pandemic has highlighted the need for early warning systems in the context of emerging and re-emerging diseases, in the same way, it constitutes a test for the usefulness and scope of the International Health Regulations (IHR) of the World Health Organization. Article 44 of the IHR establishes collaboration between State Parties, including the notification of cases of diseases that represent a threat to global health. An increase in the notification of national cases identified by other countries could be used as an alert mechanism before the appearance of a new epidemic wave.

Methods
Descriptive study of the notifications received in the IHR National Focal Point of Mexico, of cases and contacts of COVID-19 by other State Parties. Spearman’s correlation between the weekly cases and contacts with origin or destination to Mexico notified to the Focal Point and the weekly cases presented in the world and in Mexico was determined.

Results
Communications received between January 2020 and March 2022 were collected in which Mexico was notified of cases and contacts of COVID-19 with a history of travel to Mexico. The Spearman’s correlation between the cases and contacts notified to the Focal Point of Mexico and the number of new cases in the world was 0.70, while for the new cases in Mexico was 0.72.

Conclusion
The positive correlation between the notifications made by IHR State Parties to Mexico raises the possibility of being used as an alert before the appearance of epidemic waves. When assessed graphically, the peaks in notifications did not always appear in advance of the different epidemic waves of the pandemic. Factors such as the variability in the number of countries that notify or the interruption of notification by some countries during the length of the pandemic can modify and make this mechanism less reliable.