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Viral Respiratory Infection (e.g., Influenza)NCT07601126

Respiratory Pathogen Distribution During and After the COVID-19 Pandemic

An observational study of Viral Respiratory Infection (e.g., Influenza) and Bacterial Respiratory Infections, run by Hisar Intercontinental Hospital at 1 site in Turkey (Türkiye).

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This retrospective observational study aims to evaluate changes in the prevalence and distribution of respiratory pathogens detected by multiplex respiratory polymerase chain reaction (PCR) testing during and after the SARS-CoV-2 pandemic. Read more about this study

Who is it for?
Any age
How many people
537 participants
Where
1 siteTurkey (Türkiye)
Study dates
1 Jan 2021to 30 Dec 2024
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages Any age
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Study population: The study population consisted of patients presenting with respiratory infection symptoms who underwent multiplex respiratory polymerase chain reaction (PCR) testing at a tertiary care center during the pandemic and post-pandemic periods. Patients with complete demographic and laboratory data were included in the analysis.

Who may be able to join

  • Adults and/or pediatric patients presenting with respiratory infection symptoms
  • Patients who underwent multiplex respiratory PCR testing
  • Patients with complete demographic and laboratory records
  • Patients included during the defined pandemic or post-pandemic study periods

Who cannot join

  • Incomplete laboratory or demographic data
  • Duplicate test records from the same infection episode
  • Invalid or inconclusive PCR results
  • Patients without respiratory infection symptoms

Trial locations and contacts

1 site in 1 country.

Turkey (Türkiye)1 site
  • Hisar Intercontinental Hospital

    Istanbul, 34768

Other trials in Turkey (Türkiye)

About this study

Official title: Comparative Analysis of Respiratory Pathogens During and After the SARS-CoV-2 Pandemic: A Retrospective Multiplex PCR-Based Study

This retrospective observational study aims to evaluate changes in the prevalence and distribution of respiratory pathogens detected by multiplex respiratory polymerase chain reaction (PCR) testing during and after the SARS-CoV-2 pandemic. The study includes 537 patients presenting with respiratory infection symptoms at a tertiary care center. Patients were divided into pandemic-period and post-pandemic-period groups, and respiratory pathogen profiles were compared between the groups.

The study investigates the epidemiological impact of COVID-19-related public health measures on respiratory pathogen circulation patterns, including bacterial and viral respiratory infections. The findings may contribute to improved respiratory infection surveillance, diagnostic strategies, and post-pandemic public health preparedness.

Read the detailed description

The COVID-19 pandemic significantly altered the epidemiology of respiratory infections worldwide. Non-pharmaceutical interventions (NPIs), including mask use, social distancing, travel restrictions, enhanced hygiene measures, and lockdown policies, were implemented primarily to reduce SARS-CoV-2 transmission. However, these interventions also affected the circulation patterns of other respiratory pathogens.

Several studies have demonstrated substantial reductions in influenza, respiratory syncytial virus (RSV), and other respiratory viral infections during periods of strict public health measures. Following the relaxation of these interventions, many regions experienced re-emergence and altered seasonal patterns of respiratory pathogens. Continuous surveillance of respiratory infections has therefore become increasingly important for both clinical management and public health preparedness.

This retrospective observational cohort study aims to evaluate changes in respiratory pathogen prevalence during and after the SARS-CoV-2 pandemic using multiplex respiratory PCR testing data obtained from patients presenting with respiratory infection symptoms at a tertiary care center. A total of 537 patients were included and categorized into pandemic-period and post-pandemic-period groups.

Demographic characteristics and multiplex PCR results were analyzed and compared between the groups. Respiratory pathogens evaluated in the study included bacterial and viral agents such as Streptococcus pneumoniae, Haemophilus influenzae, Influenza A/B, SARS-CoV-2, RSV, Rhinovirus, Bocavirus, Parainfluenza virus, Coronavirus, and Metapneumovirus.

The study aims to contribute to understanding the long-term epidemiological effects of the COVID-19 pandemic and associated public health measures on respiratory pathogen distribution. In addition, the findings may support future infection surveillance strategies, diagnostic approaches, and healthcare preparedness in post-pandemic periods.

Keywords
Respiratory pathogens, Multiplex PCR, SARS-CoV-2, Pandemic period, Post-pandemic period
Medical subject headings
Influenza, Human

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Study groups in NCT07601126
Study groupRoleWhat they receive
Pandemic Period GroupPatients presenting with respiratory infection symptoms who underwent multiplex respiratory PCR testing during the SARS-CoV-2 pandemic period.
Post-Pandemic Period GroupPatients presenting with respiratory infection symptoms who underwent multiplex respiratory PCR testing during the post-pandemic normalization period.

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in the prevalence of respiratory pathogens between the pandemic and post-pandemic periods

    The primary outcome is the difference in detection rates of respiratory pathogens identified by multiplex respiratory PCR testing between the SARS-CoV-2 pandemic period and the post-pandemic period.

    Measured: Retrospectively assessed at the time of respiratory PCR testing during the study periods. Pandemic period: March 2020 - May 2023 Post-pandemic period: June 2023 - December 202

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted22 May 2026
  2. Study start1 Jan 2021
  3. Primary completion30 Dec 2024
  4. Study completion30 Dec 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Retrospective
Enrolment
537 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07601126
Sponsor's protocol ID
HHI-RP-PCR-2026-001
Status last verified
May 2026
First submitted
13 May 2026
Last updated
22 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: Individual participant data (IPD) will not be shared because this retrospective study contains hospital-based patient data, and sharing such data may compromise patient confidentiality and institutional data protection policies.

Publications

  • Poole S, Brendish NJ, Clark TW. SARS-CoV-2 has displaced other seasonal respiratory viruses: Results from a prospective cohort study. J Infect. 2020 Dec;81(6):966-972. doi: 10.1016/j.jinf.2020.11.010. Epub 2020 Nov 15.

    PubMed 33207254
  • Bandeira TJPG, Oliveira ALS, Martins LFP, Matos RM, Santos SRNGD, Lopes MC, Sobreira RTP, Rocha HAL. Molecular detection of respiratory viruses: an observational study on respiratory co-infections in children and adults. Braz J Microbiol. 2025 Mar;56(1):537-543. doi: 10.1007/s42770-024-01581-x. Epub 2024 Dec 17.

    PubMed 39690324
  • Le Hingrat Q, Bouzid D, Choquet C, Laurent O, Lescure FX, Timsit JF, Houhou-Fidouh N, Casalino E, Lucet JC, Descamps D, Visseaux B. Viral epidemiology and SARS-CoV-2 co-infections with other respiratory viruses during the first COVID-19 wave in Paris, France. Influenza Other Respir Viruses. 2021 Jul;15(4):425-428. doi: 10.1111/irv.12853. Epub 2021 Apr 4.

    PubMed 33817971
  • Olsen SJ, Azziz-Baumgartner E, Budd AP, Brammer L, Sullivan S, Pineda RF, Cohen C, Fry AM. Decreased influenza activity during the COVID-19 pandemic-United States, Australia, Chile, and South Africa, 2020. Am J Transplant. 2020 Dec;20(12):3681-3685. doi: 10.1111/ajt.16381.

    PubMed 33264506
  • Yam SLS, Baguio JMJ, Chan RWY. Pediatric Respiratory Viral Infection. Viruses. 2024 May 6;16(5):733. doi: 10.3390/v16050733.

    PubMed 38793615
  • Agca H, Akalin H, Saglik I, Hacimustafaoglu M, Celebi S, Ener B. Changing epidemiology of influenza and other respiratory viruses in the first year of COVID-19 pandemic. J Infect Public Health. 2021 Sep;14(9):1186-1190. doi: 10.1016/j.jiph.2021.08.004. Epub 2021 Aug 8.

    PubMed 34399190
  • Agha R, Avner JR. Delayed Seasonal RSV Surge Observed During the COVID-19 Pandemic. Pediatrics. 2021 Sep;148(3):e2021052089. doi: 10.1542/peds.2021-052089. Epub 2021 Jun 9. No abstract available.

    PubMed 34108234

Questions about this trial

What is this clinical trial studying?

An observational study of Viral Respiratory Infection (e.g., Influenza) and Bacterial Respiratory Infections, run by Hisar Intercontinental Hospital at 1 site in Turkey (Türkiye).

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 22 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in the prevalence of respiratory pathogens between the pandemic and post-pandemic periods (time frame: Retrospectively assessed at the time of respiratory PCR testing during the study periods. Pandemic period: March 2020 - May 2023 Post-pandemic period: June 2023 - December 202). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07601126, which also lists 7 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 May 2026.

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