Development of a vaccine against group B meningococci has proved much more difficult, as its surface proteins (which would normally be used to make a vaccine) only elicit a weak response from the immune system, or cross-react with normal human proteins. Still, some countries (New Zealand, Cuba, Norway and Chile) have developed vaccines against local strains of group B meningococci; some have shown good results and are used in local immunization schedules. Two new vaccines, both approved in 2014, are effective against a wider range of group B meningococci strains. In Africa, until recently, the approach for prevention and control of meningococcal epidemics was based on early detection of the disease and emergency reactive mass vaccination of the at-risk population with bivalent A/C or trivalent A/C/W135 polysaccharide vaccines, though the introduction of MenAfriVac (meningococcus group A vaccine) has demonstrated effectiveness in young people and has been described as a model for product development partnerships in resource-limited settings.Routine vaccination against Streptococcus pneumoniae with the pneumococcal conjugate vaccine (PCV), which is active against seven common serotypes of this pathogen, significantly reduces the incidence of pneumococcal meningitis. The pneumococcal polysaccharide vaccine, which covers 23 strains, is only administered to certain groups (e.g. those who have had a splenectomy, the surgical removal of the spleen); it does not elicit a significant immune response in all recipients, e.g. small children. Childhood vaccination with Bacillus Calmette-Guérin has been reported to significantly reduce the rate of tuberculous meningitis, but its waning effectiveness in adulthood has prompted a search for a better vaccine.
Aquarium granuloma (also known as fish tank granuloma and swimming pool granuloma) is a rare skin condition caused by a non-tubercular mycobacterium known as Mycobacterium marinum. Skin infections with M. marinum in humans are relatively uncommon, and are usually acquired from contact with contaminated swimming pools, aquariums or infected fish. Signs and symptoms
Aquarium granuloma presents as a slow-growing, inflamed red bump (nodule or plaque) at the site of infection. It is characterized by a painful, itchy skin lesion,  and may become ulcerated or crusted. Skin changes usually appear roughly three weeks after the aquatic exposure.If this condition is acquired from an aquarium, then often the dominant hand is affected. If this condition is acquired from a swimming pool, then symptoms can also develop on trauma-prone body zones, such as the elbows, knees, feet and tip of the nose. Cause
For the infection to develop in humans, the two main factors required are exposure to contaminated water, and abrasion or injury to the skin. Hence, this infection is commonly seen in individuals who clean fish tanks, handle ornamental fish and work in wet fields.Aquatic systems with a high density of fish and warm waters appear to be conditions particularly favorable to this infectious agent, and increase the changes to contract fish tank granuloma. Poor water quality and various nutritional deficiencies are also possible contributing factors.Swimming pool granuloma can occur when there is inadequate chlorination of swimming pools. Diagnosis
Aquarium granuloma is relatively nonspecific in clinical presentation.