Findings 81?430 nasopharyngeal samples were collected from 1116 participants in 225 households (follow-up rate 88%). 917 (1%) tested positive for influenza; 178 (79%) of 225 households had one or more influenza-positive individual. The incidence of influenza infection was 43·6 (95% CI 39·8–47·7) per 100 person-seasons. 69 (17%) of 408 individuals who had one influenza infection had a repeat influenza infection during the same season. The incidence (67·4 per 100 person-seasons) and proportion with repeat infections (22 [23%] of 97 children) were highest in children younger than 5 years and decreased with increasing age (p<0·0001). Overall, 268 (56%) of 478 infections were symptomatic and 66 (14%) of 478 infections were medically attended. The overall HCIR was 10% (109 of 1088 exposed household members infected [95% CI 9–13%). Transmission (HCIR) from index cases was highest in participants aged 1–4 years (16%; 40 of 252 exposed household members) and individuals with two or more symptoms (17%; 68 of 396 exposed household members). Individuals with asymptomatic influenza transmitted infection to 29 (6%) of 509 household contacts. HIV infection, affecting 167 (16%) of 1075 individuals, was not associated with increased incidence or HCIR. Interpretation Approximately half of influenza infections were symptomatic, with asymptomatic individuals transmitting influenza to 6% of household contacts. This suggests that strategies, such as quarantine and isolation, might be ineffective to control influenza. Vaccination of children, with the aim of reducing influenza transmission might be effective in African settings given the young population and high influenza burden.
Influenza, whether of the seasonal or pandemic variety, is asymptomatic in most people with serologically confirmed infection, according to a study in the Lancet Respiratory Medicine.
Researchers studied five successive cohorts of people in England during the 2006-2011 flu seasons. The cohorts ranged in size from 600 to 3500, and all members provided blood samples before and after each flu season. Their households were contacted weekly to identify flu-like illness and symptoms.
On average, roughly 20% of the unvaccinated had serologic evidence of influenza infection, but up to three quarters of the infected were asymptomatic. The proportions did not vary significantly between seasonal and pandemic influenzas. The pandemic H1N1 strain was associated with less severe symptoms than the seasonal H3N2 strain.
A commentator says an important unanswered question is how much the asymptomatic cases contribute to flu transmission
The commonly cited 5% to 20% estimate was based on a study that examined both symptomatic and asymptomatic influenza illness, which means it also looked at people who may have had the flu but never knew it because they didn’t have any symptoms. The 3% to 11% range is an estimate of the proportion of people who have symptomatic flu illness.
However, did you know that one out of every three individuals with seasonal flu infections may be asymptomatic? This is thought to be caused by pre-existing partial immunity. Certain individuals have immune systems that shed the virus and transmit the disease, but not at the same rate as patients who go on to develop symptoms. The way that certain people’s immune systems handle flu may allow them to fight the disease without displaying typical flu symptoms.
Because it is still possible for asymptomatic individuals to transmit flu, it is always important to take precautions and practice good hygiene. Cover your mouth with your elbow when you cough or sneeze, and wash your hands regularly with soap and warm water. Do your best to avoid touching your face when your hands have not just been washed.
https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(21)00141-8/fulltext
Findings 81?430 nasopharyngeal samples were collected from 1116 participants in 225 households (follow-up rate 88%). 917 (1%) tested positive for influenza; 178 (79%) of 225 households had one or more influenza-positive individual. The incidence of influenza infection was 43·6 (95% CI 39·8–47·7) per 100 person-seasons. 69 (17%) of 408 individuals who had one influenza infection had a repeat influenza infection during the same season. The incidence (67·4 per 100 person-seasons) and proportion with repeat infections (22 [23%] of 97 children) were highest in children younger than 5 years and decreased with increasing age (p<0·0001). Overall, 268 (56%) of 478 infections were symptomatic and 66 (14%) of 478 infections were medically attended. The overall HCIR was 10% (109 of 1088 exposed household members infected [95% CI 9–13%). Transmission (HCIR) from index cases was highest in participants aged 1–4 years (16%; 40 of 252 exposed household members) and individuals with two or more symptoms (17%; 68 of 396 exposed household members). Individuals with asymptomatic influenza transmitted infection to 29 (6%) of 509 household contacts. HIV infection, affecting 167 (16%) of 1075 individuals, was not associated with increased incidence or HCIR. Interpretation Approximately half of influenza infections were symptomatic, with asymptomatic individuals transmitting influenza to 6% of household contacts. This suggests that strategies, such as quarantine and isolation, might be ineffective to control influenza. Vaccination of children, with the aim of reducing influenza transmission might be effective in African settings given the young population and high influenza burden.https://www.jwatch.org/fw108600/2014/03/17/most-flu-asymptomatic
Most Flu Is AsymptomaticBy Joe Elia
Influenza, whether of the seasonal or pandemic variety, is asymptomatic in most people with serologically confirmed infection, according to a study in the Lancet Respiratory Medicine.
Researchers studied five successive cohorts of people in England during the 2006-2011 flu seasons. The cohorts ranged in size from 600 to 3500, and all members provided blood samples before and after each flu season. Their households were contacted weekly to identify flu-like illness and symptoms.
On average, roughly 20% of the unvaccinated had serologic evidence of influenza infection, but up to three quarters of the infected were asymptomatic. The proportions did not vary significantly between seasonal and pandemic influenzas. The pandemic H1N1 strain was associated with less severe symptoms than the seasonal H3N2 strain.
A commentator says an important unanswered question is how much the asymptomatic cases contribute to flu transmission
https://www.cdc.gov/flu/about/keyfacts.htm
The commonly cited 5% to 20% estimate was based on a study that examined both symptomatic and asymptomatic influenza illness, which means it also looked at people who may have had the flu but never knew it because they didn’t have any symptoms. The 3% to 11% range is an estimate of the proportion of people who have symptomatic flu illness.
https://hhma.org/can-the-flu-be-asymptomatic/
However, did you know that one out of every three individuals with seasonal flu infections may be asymptomatic? This is thought to be caused by pre-existing partial immunity. Certain individuals have immune systems that shed the virus and transmit the disease, but not at the same rate as patients who go on to develop symptoms. The way that certain people’s immune systems handle flu may allow them to fight the disease without displaying typical flu symptoms.
Because it is still possible for asymptomatic individuals to transmit flu, it is always important to take precautions and practice good hygiene. Cover your mouth with your elbow when you cough or sneeze, and wash your hands regularly with soap and warm water. Do your best to avoid touching your face when your hands have not just been washed.
没用。
胡搅蛮缠是TA们的本性。
该说啥说啥,不要跟他们纠缠就好。
中医也学得胡思乱想那种。