Reply to "no clinical association of live attenuated influenza vaccine with nasal carriage of bacteria or acute otitis media": specific recommendations for future studies.

Abstract

Recently, we reported that vaccinating mice with a live attenuated influenza vaccine (LAIV) led to substantial increases in the dynamics of nasal colonization by important and common bacterial respiratory pathogens, including Streptococcus pneumoniae and Staphylococcus aureus (1). However, as Coelingh and Belshe point out (2) and as we emphasize both in that paper and again here, in contrast to what occurred when mice were vaccinated against seasonal influenza viruses, mice vaccinated with LAIV did not exhibit increased susceptibility to bacterial disease in the lower respiratory tract, which is of particular concern when considering what is known about interactions between influenza viruses and bacterial pathogens (3). Our investigation received considerable attention, but unfortunately, a large portion of it came from the antivaccine movement. This is not surprising, as our results—the first to demonstrate an increased level of one pathogen as a result of a vaccine targeted against an unrelated pathogen—can easily, perhaps intentionally, be misinterpreted to seem as though our data advocate against the use of live attenuated influenza vaccines. This is not the case, and we agree firmly with the overwhelming data demonstrating that both LAIV and inactivated influenza vaccines are beneficial in reducing influenza-related disease (4), including from bacterial infections (5, 6). What we demonstrated in our report (1) is that an LAIV induced excess replication of multiple bacterial pathogens in the upper respiratory tracts of mice without causing consequent lower respiratory tract disease. What do the clinical data show? Citing the abstract (7) of a randomized placebo-controlled study of LAIV ( n = 151 children) by Thors et al. submitted for presentation …