POLIO IMMUNIZATION AND THE HERD EFFECT.
D006801:Humans; D007114:Immunization; D011051:Poliomyelitis; D023321:Poliovirus Vaccines; D013223:Statistics as Topic; D013548:Sweden; D014481:United States; D014611:Vaccination
D023321:Poliovirus Vaccines
IMMUNIZATION; POLIOMYELITIS; POLIOVIRUS VACCINE; STATISTICS; SWEDEN; UNITED STATES