tetano
Editor, Senior Moderator
Respir Care. 2012 Mar 12. [Epub ahead of print]
Clinical and Epidemiological Features of 2009 Pandemic H1N1 Influenza Differ Slightly According to Seroprevalence Status During the Second Wave in the General Population in Mexico.
Elizondo-Montemayor L, Hern?ndez-Torre M, Ugalde-Casas PA, Santos-Guzm?n J, Serrano-Gonz?lez M, Guti?rrez NG, Lam-Franco L, Tamargo-Barrera D, Mart?nez U, Bustamante-Careaga H, Alvarez MM, Schultz-Cherry S.
Abstract
BACKGROUND:
Clinical features of pandemic H1N1 have been derived from lab-confirmed, hospitalized or critically ill subjects. This report describes the clinical features of H1N1 and their prevalence from non-confirmed subjects according to seroprevalence status in Mexico. The objective was to determine the prevalence of these clinical features from non-confirmed cases of pandemic H1N1 and to compare them according to seroprevalence status in northern Monterrey, Mexico during 2009, and to identify the predictive signs and symptoms, as there have been no prior serologic studies in Mexico.
METHODS:
During November-December 2009, 2,222 volunteers aged 6-99y were categorized into three symptomatic groups: influenza-like illness, respiratory illness, and non respiratory illness. Antibodies against influenza A/H1N1/2009 were determined by a virus-free ELISA method. Demographics and clinical presentation were assessed through face-to-face questionnaire, and the association with seroprevalence status was determined and compared.
RESULTS:
Overall seroprevalence was 39%. Of the seropositive subjects, 67% were symptomatic and 33% asymptomatic. 71% of seropositive symptomatic subjects reported respiratory illness, 17% non-respiratory symptoms and 12% influenza-like illness. The most common symptoms were rhinorrhea/nasal congestion (93%) and headache (83%). No significant difference was found between the symptom profiles of the seropositive group, compared to the seronegative one, nor of the median duration of symptoms. The seropositive group had significantly elevated proportion of influenza-like illness (12%) compared to the seronegative one (8%). The proportion of subjects who took days off and who sought medical attention was significantly higher in the seropositive group. Nosingle symptom was associated as predictor of seropositiveness.
CONCLUSION:
One third of the seropositive subjects were asymptomatic and few had an influenza-like illness. No difference was found in the symptom profiles of the seropositive and seronegative groups. No single symptom predicted seropositiveness. Large scale population studies are needed, especially in Mexico, to characterize clinical syndromes.
PMID:
22418453
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22418453
Clinical and Epidemiological Features of 2009 Pandemic H1N1 Influenza Differ Slightly According to Seroprevalence Status During the Second Wave in the General Population in Mexico.
Elizondo-Montemayor L, Hern?ndez-Torre M, Ugalde-Casas PA, Santos-Guzm?n J, Serrano-Gonz?lez M, Guti?rrez NG, Lam-Franco L, Tamargo-Barrera D, Mart?nez U, Bustamante-Careaga H, Alvarez MM, Schultz-Cherry S.
Abstract
BACKGROUND:
Clinical features of pandemic H1N1 have been derived from lab-confirmed, hospitalized or critically ill subjects. This report describes the clinical features of H1N1 and their prevalence from non-confirmed subjects according to seroprevalence status in Mexico. The objective was to determine the prevalence of these clinical features from non-confirmed cases of pandemic H1N1 and to compare them according to seroprevalence status in northern Monterrey, Mexico during 2009, and to identify the predictive signs and symptoms, as there have been no prior serologic studies in Mexico.
METHODS:
During November-December 2009, 2,222 volunteers aged 6-99y were categorized into three symptomatic groups: influenza-like illness, respiratory illness, and non respiratory illness. Antibodies against influenza A/H1N1/2009 were determined by a virus-free ELISA method. Demographics and clinical presentation were assessed through face-to-face questionnaire, and the association with seroprevalence status was determined and compared.
RESULTS:
Overall seroprevalence was 39%. Of the seropositive subjects, 67% were symptomatic and 33% asymptomatic. 71% of seropositive symptomatic subjects reported respiratory illness, 17% non-respiratory symptoms and 12% influenza-like illness. The most common symptoms were rhinorrhea/nasal congestion (93%) and headache (83%). No significant difference was found between the symptom profiles of the seropositive group, compared to the seronegative one, nor of the median duration of symptoms. The seropositive group had significantly elevated proportion of influenza-like illness (12%) compared to the seronegative one (8%). The proportion of subjects who took days off and who sought medical attention was significantly higher in the seropositive group. Nosingle symptom was associated as predictor of seropositiveness.
CONCLUSION:
One third of the seropositive subjects were asymptomatic and few had an influenza-like illness. No difference was found in the symptom profiles of the seropositive and seronegative groups. No single symptom predicted seropositiveness. Large scale population studies are needed, especially in Mexico, to characterize clinical syndromes.
PMID:
22418453
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/22418453