Phylogenetic and antigenic analysis of influenza A(H3N2) viruses isolated from conscripts receiving influenza vaccine prior to the epidemic season of 1998/9.
Epidemiol Infect
; 129(2): 347-53, 2002 Oct.
Article
en En
| MEDLINE
| ID: mdl-12403110
ABSTRACT
Roughly half (54%) of the 910 young conscripts at a garrison in Finland were vaccinated with commercial influenza vaccines in autumn 1998. During the influenza outbreak in February 1999, 12 H3N2-subtype virus strains were isolated from vaccinated patients, and 11 such strains were isolated from unvaccinated patients. The isolates were related to the vaccine strain A/Sydney/5/97 and could be classified into three subgroups based on sequence variation in the HA1 gene coding for the variable domain of viral haemagglutinin (HA). A total of 6-10 amino-acid substitutions in HA1, three of these in the receptor-binding site, differentiated the field strains from the vaccine virus. In haemagglutination inhibition (HI) tests, eight strains from the study population exhibited reduced reactivity with a variety of antisera including human post-vaccination sera. Six of these strains were isolated from vaccinated and two from unvaccinated patients. The reduced reactivity did not correlate with particular amino-acid changes in HA1. We suggest that low-reactivity viruses may have an advantage over other co-circulating variants under some circumstances characterized by enhanced immunity-mediated selection and high infection pressure. Whether the frequency of these viruses increased in our vaccinated study population cannot be determined, nor can their effect on vaccine efficacy.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Virus de la Influenza A
/
Vacunas contra la Influenza
/
Gripe Humana
/
Subtipo H3N2 del Virus de la Influenza A
Tipo de estudio:
Observational_studies
/
Risk_factors_studies
Límite:
Adult
/
Humans
/
Male
País/Región como asunto:
Europa
Idioma:
En
Revista:
Epidemiol Infect
Asunto de la revista:
DOENCAS TRANSMISSIVEIS
/
EPIDEMIOLOGIA
Año:
2002
Tipo del documento:
Article
País de afiliación:
Finlandia