Competition between 2 serotypes

1. Direct

1.1. being colonized

1.1.1. protects against other colonization

1.1.1.1. Bactericide secretion

1.1.1.2. Sampling difficuties....

1.1.1.3. 6B

1.1.1.3.1. colonized individuals have lower risk of being colonized

1.2. Double colonization

1.2.1. accelerates colonization clearage

1.2.2. reduces infectiousness

2. Indirect

2.1. No serotype replacement possible

2.2. immunity to 1 strain

2.2.1. partial immunity to colonization of another

2.2.1.1. 2008 - 2y - carriage

2.2.1.1.1. homologous protection = immunity to same

2.2.1.1.2. heterologous protection

2.2.1.2. 2009 - 1y - carriage

2.2.1.2.1. heterologous protection

2.2.1.3. vaccine-related serotypes

2.2.1.3.1. 6A

2.2.1.3.2. 9A,L,N

2.2.1.3.3. 18A,B,F

2.2.1.3.4. 19A(B,C)

2.2.1.3.5. 23A,B

2.2.2. quicker clearage of second colonization

2.2.3. reduced force of infection