[Analysis on influenza antibodies detection rate and infected recently among infants].
OBJECTIVE
To understand the status of infants infected with influenza viruses after switch over of dominant strain in the summer of 2006.


METHODS
Two groups of infants serum were collected and to be detected the antibodies of influenza viruses which the infants experienced two peaks of influenza A H1N1 circulation in the age of 3-4 and 10-11 months old and the infants only experience one circulation in 5-6 months old.


RESULTS
The antibody of influenza A H1N1 viruses was 31.47% in the infants who experience two circulations in 3-4 months and 10-11 months old and was 26.42% which only experience circulation in the 5-6 months old. There were no significant difference between 2 groups (chi2 = 1.207, P > 0.05).


CONCLUSIONS
The group of 13 months age of infants were rarely infected influenza virus in the first time exposure at the age of < or =4 months due to maternal antibodies protection. Whenas, the group of 8 months age who were exposed at the age of > or =5 months, were more easier infected the influenza virus than the group of 13 months age in the first time exposure at the age of < or =4 months.
Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010, Zhejiang, China.
Feng-jiao
FJ
Hu
Hong-xia
HX
Ni
Su-li
SL
Jiao
D000914:Antibodies, Viral / Q000097:blood*; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology; D007251:Influenza, Human / Q000097:blood / Q000175:diagnosis / Q000276:immunology* / Q000821:virology*; D009975:Orthomyxoviridae / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification* / Q000502:physiology; D013997:Time Factors
D000914:Antibodies, Viral