Objective: PCV effects on S. pneumoniae and S. aureus carriage in a population based study. The major specific aims:

1. To compare different PCV vaccination policies, by cross-sectional repeated surveillance of closely related populations living in regions with different vaccination policies.
2. To compare the epidemiology, predictors and outcomes of antibiotic resistant S. aureus and S. pneumoniae in different regions of the PICR.

Study design: Annual / Biannual cross-sectional surveillance of nasal S. aureus carriage and nasopharyngeal S. pneumoniae carriage in children and one of their parents.

Study design: Annual / Biannual cross-sectional surveillance of nasal S. aureus carriage and nasopharyngeal S. pneumoniae carriage in children and one of their parents.

PICR districts: 1. Palestinian Authority (PA) - particularly: Bethlehem, Ramallah and Nabulus. 2. East Jerusalem (EJ) 3. Central Israel (IL) - particularly: Rishon Lezion, Bat Yam, Holon 4. Gaza strip (GZ) - 12 regions including cities/villages in central/northern Gaza.

Study population:

Child (age 0-5y) & Parent who attend clinics (for any reason).

Exclusion criteria:

Parent does not agree to sign informed consent Child or sibling (brother/sister) have already participated.

Both healthy and ill children are screened. No specific exclusion other than the above.

Only one child per family (younger child, if more than one available) and one parent (mother, if both are available).

Sample size per year:

IL: Central Israel (Hashfela District): 400 pairs of child+parent/surveillance EJ: East Jerusalem: 400 pairs of child+parent/surveillance PA: West Bank cities (Ramallah, Bethlehem & Nabulus): 600 pairs of child+parent/surveillance GZ: Gaza strip: 300 pairs of child+parent/surveillance

Study Period:

May-August annually 2009 - 2011 - (Part a). May-August biannually 2014-2016-2018-2020 Current study (Part b).

Screening Procedure:

1. Parent signs informed consent
2. Put Barcode stickers on informed consent, questionnaire, swabs and daily list
3. Fill questionnaire with parent.
4. Fill physician questionnaire
5. Nasal & nasopharyngeal swab of child and parent.
6. Fill daily working table.
7. Write the number of refusals (parents who refused) on daily table.
8. Fill questionnaire FULLY (unmarked questions will not be analyzed) - put x on each question - whether YES or NO.

Swabbing:

1. First swab the child and then follow with the parent.
2. First perform nasal swab (for S. aureus) using cotton-tip swab placed into Amies transport Media (Blue) and follow with nasopharyngeal swab ( for S. pneumoniae) using rayon-tipped aluminum shaft swab placed in Amies transport Media (Orange).
3. Slightly wet the nasal swab with sterile saline. Swab both anterior nares.
4. Nasopharyngeal swab of only through one nostril - gently, quickly and deep to nasopharynx - until you touch the nasopharyngeal wall.

Swab transfer to lab:

If swabs are stored overnight before transfer - keep in 40C (fridge). Within 24h swabs must reach the central laboratory (Dr. Regev-Yochay's Lab at Sheba Medical Center).

Inclusion Criteria:

• Any child younger than 5 years, visiting the participating clinics during the surveillance period

Exclusion Criteria:

• Older than 5 years
• Previously participated in the study.
• Sibling has participated in the study.
• Parent does not agree to sign informed consent

Child (age 0-5y) & Parent who attend pediatric clinics (for any reason), in the participating clinics during the surveillance periods.