[1] Poznan Univ Med Sci, Dept Neonatol, PL-60535 Poznan, Poland
[2] Pfizer Vaccine Res, Maidenhead, Berks, England
[3] Poznan Univ Med Sci, Dept Prevent Med, PL-60535 Poznan, Poland
[4] Family Specialist Outpatient Clin, Phys Practice Grp, Torun, Poland
[5] Wl Bieganski Prov Specialist Hosp Lodz, Lodz, Poland
[6] St Luis Prov Specialist Childrens Hosp, Krakow, Poland
[7] Dr Biziel Univ Hosp 2 Bydgoszcz, Bydgoszcz, Poland
[8] Univ Childrens Hosp Cracow, Krakow, Poland
[9] Pfizer Inc, Vaccine Res, Pearl River, NY USA
[10] Pfizer Inc, Pfizer Vaccines Res, Collegeville, PA USA
[11] Pfizer Inc, Maidenhead, Berks, England
[12] Pfizer Vaccines Res, Pearl River, NY USA