Table 2. Questions left unanswered with regard to Active Bacterial Core surveillance*.

Organism or disease	Questions
Streptococcus pneumoniae	Should PCV13 be recommended for adults?
	What proportion of invasive pneumococcal disease is preventable with vaccine?
	What other strategies are available to prevent non–vaccine type disease?
Neisseria meningitidis	Should serogroup B vaccines be recommended for routine use in the United States?
Haemophilus influenzae	Are control strategies (e.g., chemoprophylaxis, vaccines) needed for non-Hib disease?
Group B Streptococcus	Will antimicrobial drug resistance reduce the effectiveness of intrapartum prophylaxis?
	What will be the projected effect of vaccines on infant disease?
	Are there interventions to reduce infant late-onset disease?
Group A Streptococcus	What age groups should be targeted for vaccines according to potential effect on invasive disease?
MRSA	Can modifiable risk factors for HACO MRSA be identified?
	What are effective strategies for preventing infections outside acute-care settings?
Pertussis	Does the acellular vaccine given during pregnancy effectively prevent pertussis in infants?
	What is the effect of newly emerging Bordatella pertussis strain changes on disease epidemiology, clinical presentation, and vaccine effectiveness?
Legionellosis	Why are rates higher among black than white persons and higher among men than women?
	Why do rates differ by geographic area?

*PCV13, 13-valent pneumococcal conjugate vaccine; Hib, H. influenzae type b; HACO, health care–associated community onset; MRSA, methicillin-resistant Staphylococcus aureus.