RESUMO
Bacille Calmette-Guerin [BCG] vaccination is part of the expanded program of vaccination in Saudi Arabia. Lymphadenitis is the most common complication of the BCG vaccine. We observed an increase in the rate of BCG lymphadenitis that coincided with the introduction of a new strain of BCG vaccine. The aim of this study was to determine the incidence and the possible causes of BCG lymphadenitis at a university hospital in Riyadh, Saudi Arabia. Retrospective chart review and prospective follow up of infants who received BCG vaccine. We studied all infants presenting with suppurative or nonsuppurative adenopathy with nodes >/= 2 cm seen at the infectious diseases clinic at KKUH. The study duration was divided into two periods. The first period reviewed infants who received different BCG vaccine strains between January 2002 and December 2007. The second study period was conducted after close evaluation of the BCG administration technique of the vaccinating staff and reviewed infants who received the BCG SSI Danish strain 1331 between January 2008 and December 2010.During the study period from January 2002 to December 2007, 19 402 infants received four different BCG vaccine strains. Eight infants developed BCG lymphadenitis, and all were associated with the BCG SSI vaccine. The incidence rate in 2007 was 1.96 per 1000. In the second period, 66 of 9921 infants who received the BCG SSI vaccine developed BCG lymphadenitis between January 2008 and December 2010. The incidence rate was 10.14 per 1000 in 2010. We conclude that receipt of the BCG SSI vaccine might have contributed to the increased incidence of lymphadenitis in these children. Hence, caution should be exercised in switching from one vaccine to another, as is often done in developing countries