This may have led to misclassifications of illness, especially for pneumonia and fever.
Relying on maternal self-report could have resulted in misclassification of infant illness status.
Therefore, misclassification of persons with illnesses other than pandemic (H1N1) 2009 may have occurred.
We also performed an analysis restricted to participants swabbed within 4 days of illness onset because of potential misclassification bias with delayed sample collection.
Other possible bias includes recall and information bias (history of illness and seizures from parental report) and misclassification error resulting from definitions used for classifying iron deficiency.
To reduce the potential outcome misclassification, this outcome was dichotomised, considering health-seeking within one day of illness onset as timely.
Nonetheless, as elegantly demonstrated in the literature, enforcement of negative cultures among controls of a case control study can introduce a severity of illness bias, which has a more severe effect on the odds ratios than does misclassification bias [ 48].
"The type of illness is not important.
There were no reports of illness.
Increased risk of illness at this time".
