[Active surveillance of adverse effects of Pandemrix vaccine to prevent influenza A(H1N1) in Cuba].

Abstract

Introduction: in April 2009, a new virus was identified in Mexico and North America as the cause of a respiratory disease. The virus quickly spread over other countries. On June 11, 2009 the World Health Organization (WHO) reported cases in 74 countries and territories located in 2 of its regions. The high sustained transmission of this virus worldwide led to establish the phase 6 or the pandemic phase, indicating that the situation had to do with spreading rather than increased severity.

Objectives: to report on already known or new events after the administration of vaccine A(H1N1) called Pandemrix, to identify the most frequent events occurred in pregnant women and to research into the associated severe events.

Methods: a prospective descriptive study was designed to characterize the adverse effects of Pandemrix reported across the country from April 1st to June 30th, 2010. A total of 1,123,526 people were vaccinated in which 100% of pregnant women were included.

Results: active surveillance nationwide reported 5 763 signs and symptoms detected in 3 401 people (615 reports from pregnant women). The overall rate of reports was 302.7 x 100 000 doses administered. Adverse events such as fever, headache, pain, swelling and redness at the injection site, malaise, arthralgia, allergic reactions, nausea and vomiting were reported as common symptoms. These 10 symptoms and signs accounted for 79.1% of all the reported events. A total number of 80 317 pregnant women were vaccinated of whom 615 reported adverse effects, accounting for 0.8 % of the vaccinated pregnant women. Fever was the most notified symptom in children (193) followed by local reactions at the injection site (23), vomiting (20), arthralgia (17), headache (11), malaise (10) and high fever-related seizures (6). Eight events were analyzed as severe.

Conclusions: the administration of the vaccine was related to 3 events, unrelated to other 3 events and 2 were classified as inconclusive (3 miscarriages). No deaths were reported. The capacity of the Cuban Health System for the administration of this vaccine with active surveillance in a short period of time was proved. Data from monitoring of events that were supposedly attributable to vaccination or immunization did not notify any unusual event. Therefore, no safety problem is associated to the Pandemrix vaccine.