The main objective is to estimate the annual symptomatic incidence of Bordetella pertussis and RSV infections in patients aged 18 years and over with asthma, which will be identified by PCR, for Bordetella pertussis and by PCR for RSV performed at a specific timepoint from onset of symptoms for each symptomatic Acute Respiratory Infection (ARI).

A multicentre prospective cohort study will be undertaken in Spain. Thirty-five centres from different autonomous communities in Spain will participate in the study.

Participants will be asked to report to the investigator if they experience an asthma exacerbation or symptoms of acute respiratory infection with 2 years follow up

The main objective is to estimate the annual symptomatic incidence of Bordetella pertussis and RSV infections in patients aged 18 years and over with asthma, which will be identified by PCR, for Bordetella pertussis and by PCR for RSV performed at a specific timepoint from onset of symptoms for each symptomatic Acute Respiratory Infection (ARI).

A multicentre prospective cohort study will be undertaken in Spain. Thirty-five centres from different autonomous communities in Spain will participate in the study.

Participants will be asked to report to the investigator if they experience an asthma exacerbation or symptoms of acute respiratory infection with 2 years follow up

Depending on the symptoms presented and date of symptom onset, For pertussis, patients will undergo a nasopharyngeal swab specimen for PCR if onset of the symptoms was within the past 3 weeks For RSV, patients will undergo a nasopharyngeal swab specimen for PCR if onset of the symptoms was within the past 72 hours.

Inclusion Criteria:

• Adult patient (age 18 years and over)
• Diagnosed with asthma at least one year prior to the date of enrolment.
• Patients who, in the opinion of the investigator, can and will comply with the requirements of the study protocol for the duration of the follow-up period (e.g. agree to provide samples for testing, able to attend for testing upon asthma exacerbation and/or ARI symptoms occurring)
• Patients who are able to provide written informed consent.

Exclusion Criteria:

• Patients with a prior history of pertussis in the last 12 months
• Patients with ARI within the 2 weeks prior to enrolment
• Patients who have another respiratory disease other than asthma, alcohol or drug abuse at the time of being included in the study, or an active oncological disease (patients in treatment or follow-up for oncological disease) or pregnant women.
• Patients treated with immunosuppressive or immunomodulating agents not related to asthma diagnosis. will be excluded.
• Patients vaccinated for RSV will be also excluded (NOTE: -Patients that have received an RSV (investigational) vaccine or medicine for any of the above, should be excluded from the study from the beginning. Patients that might be vaccinated in the upcoming years, while the study is still ongoing, can enrol. However, from the moment they receive a vaccine, they should be excluded and no additional data will be collected. Data collected during the study up until the time of vaccination will still be included in the analysis).
• Patients vaccinated for B. Pertussis during the previous 12 months will be also excluded.
• Patients who plan to move during the study period will be excluded.

Consecutive adult patients (18 years and over) with asthma diagnosed at least one year before will be enrolled from the asthma clinics of selected hospitals.

Every group (at each participating site) should include 35% of patients over 60 years old considering that this age-group has higher risk of infection and worse prognosis than the younger one.