Infectious Diseases include Antibiotic, antiviral, and antifungal agents to treat infections, when pathogenic microorganisms harm healthy human cells. Bacteria, viruses, and fungi often mutate and become resistant, creating a perpetual opportunity for the industry.
The major opportunity is for anti-infectives against hospital-acquired infections, which rapidly develop resistance and are associated with significant mortality and morbidity.  
Vaccines and HIV treatments form a large segment of this category. Convenience is the key in HIV treatment, and the dawn of the new classes of therapies could result in a paradigm shift in treatment. Vaccines, which offer protection against bacterial and viral diseases, face several challenges, but large markets and new technologies should continue to drive development and success.