Chronic cough can occur in children of all ages, and the incidence rate and consultation rate increase each year.Clarifying the cause of chronic cough is the key to treatment.At present, there are no convenient, operable and unified standards for etiological analysis of chronic cough in the world.Therefore, the etiological analysis of chronic cough has always been a hot topic in clinical research.With the development of diagnosis and treatment technology, the role of pulmonary function and exhaled nitric oxide in the diagnosis of chronic cough has attracted attention.This article reviews the application value of pulmonary function combined with exhaled nitric oxide in etiology analysis of chronic cough in children, to provide reference for etiology analysis of chronic cough in children.

Objective To investigate the dynamic changes of three types of anti-poliovirus neutralizing antibodies and anti-hepatitis A virus (HAV) IgG antibody in children who were immunized with inactivated enterovirus 71 (EV71) vaccine (human diploid cell).Methods Serum samples were collected from the subjects immunized with inactivated EV71 vaccine.Neutralizing antibodies against EV71 and poliovirus were detected by micro-cytopathic effect neutralization test.Enzyme linked immunosorbent assay (ELISA) was used to detect IgG antibody against HAV.Results The geometric mean titers (GMTs) of anti-EV71 neutralizing antibody increased to 4.85 following the first-dose injection of inactivated EV71 vaccine.A significant increase of GMTs (up to 64.37) could be observed 28 days after the second-dose vaccination.Meanwhile, results of the dynamic monitor showed that there were slight fluctuations in the neutralizing antibodies against three types of poliovirus on day 28 (28 days after the first-dose vaccination) compared with those on day 0 (before vaccination) (P<0.05);types Ⅰ and Ⅲ anti-poliovirus neutralizing antibodies on day 56 (28 days after the second-dose vaccination) remained slightly different from those on day 0 (P<0.05), but type Ⅱ anti-poliovirus neutralizing antibody on day 56 had restored to normal level (P>0.05).The level of anti-HAV IgG antibody was stable and no significant difference was found during the observation period (P>0.05).Conclusion This study shows that inactivated EV71 vaccine has no impact on anti-HAV IgG antibody in Children during the two-dose vaccination and in anti-EV71 antibody-producing period, but has slight influence on the anti-poliovirus antibodies.In general, changes in antibody profile do not affect the clinical efficacy of immune response.