A Simultaneous Outbreak of Meningococcal and Influenza Infections

Abstract

During a nine-day period in January, 1968, 11 cases of systemic Group B, sulfonamide-resistant Neisseria meningitidis infections with three deaths occurred among 55 elderly women confined to a single ward in a mental institution. Organisms were recovered from four patients and from five carriers. A fourfold increase in serum antibody activity to N. meningitidis antigens was found in all patients surviving systemic infection. A concurrent outbreak of A2 influenza affecting 50 per cent of this population was also documented. Serologic evidence of systemic infection or nasopharyngeal carriage of N. meningitidis, was found to be significantly associated with serologic evidence of influenza infection (p equal to 0.029). The most likely hypothesis is that influenza may enhance the acquisition of meningococci after exposure to these bacteria.