Condition category
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Upper respiratory tract infections (URTI) in children, which include the common cold and coughs, present a considerable healthcare burden involving not only the cost of direct medical care but also that incurred due to parental absence from work to look after sick children. Antibiotics are often used inappropriately for the treatment of these infections, leading to the development of bacterial resistance. In the pilot PROCHILD study (ISRCTN28722693), supplementation with the Lab4 probiotic consortium and vitamin C showed a significant reduction in the incidence rate and number of days with URTI symptoms in preschool children aged 3-6 years. The aim of this study is to extend these findings to children attending preschool facilities and primary school.

Who can participate?
Children who attend preschool (3-6 years old) or Stage 1 of primary school (1st-4th grade; 7-10 years old)

What does the study involve?
Children will be randomly allocated to take daily either one chewable tablet of probiotics in combination with vitamin C or a placebo (dummy) for 6 months. The parents/guardians of the children and the research team will be unaware of who is taking what. At the start of the study, the children will be examined by a paediatric physician and background information (age, BMI, history of allergy, regular medication) will be recorded. Parents/guardians will need to complete a diet habit and physical activity pattern questionnaire at the beginning of the study and upon completion. During the 6-month study period, the parents/guardians will complete daily health diaries including the children’s antibiotic use and any absence from preschool/primary school. The children will be examined by a paediatric physician at prescheduled 2, 4 and 6-month appointments or during unscheduled visits. Stool samples will be collected on a voluntary basis at the start and end of the study.

What are the possible benefits and risks of participating?
Supplementation with a probiotic and vitamin C combination may be beneficial in the management of upper respiratory tract infections. There were no adverse reactions associated with the active intervention in the previous PROCHILD study (ISRCTN28722693). The active and placebo tablets have been tested for the absence of Coliforms, Salmonella, yeasts and moulds and heavy metals at an independent testing laboratory (EUROFINS BEL/NOVAMANN s.r.o, Nove Zamky, Slovakia).

Where is the study run from?
Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Comenius University, Bratislava, Slovakia

When is the study starting and how long is it expected to run for?
December 2016 to December 2018

Who is funding the study?
Cultech Ltd., Port Talbot, UK

Who is the main contact?
Associate Professor Jana Muchova, PhD

Trial website

Contact information



Primary contact

Prof Jana Muchova


Contact details

Institute of medical chemistry
biochemistry and clinical biochemistry Faculty of Medicine Comenius University in Bratislava
Sasinkova 2
+42 1290119411

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

An investigation of the efficacy of long term consumption of a probiotic and vitamin C combination on the prevention of upper respiratory tract infections in children attending preschool or primary school



Study hypothesis

Long-term supplementation with Lab4 probiotic and vitamin C combination would be beneficial in the management of upper respiratory infections in children attending pre-school or Stage 1 (1st -4th grade) of primary school

Ethics approval

Approved 29/11/2016 Ethics committee of Bratislava self-governing region (Sabinovská 16, PO Box 106, 82005 Bratislava, Slovakia; Tel: +421 (0)2 48264912; Email:, ref: 07878/2016-HF

Study design

Multicentre randomised double-blind placebo-controlled study

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details to request a participant information sheet


Respiratory tract infections in children


Eligible subjects will be allocated in a 1:1 ratio to the two arms of the study according to a computer-generated random sequence using block randomisation with a block-size of four and stratified by centre. The randomisation will be performed by the statistician, who will have no contact with the participants. Participants will be enrolled and assigned sequentially to interventions by the paediatric physicians. The research team and parents/guardians will be unaware of the group assignments.

Participants randomised to active or placebo group will be required to take one chewable tablet per day for 6 months:
1. Active intervention contains the Lab4 probiotic consortium (Lactobacillus acidophilus CUL60, Lactobacillus acidophilus CUL21, Bifidobacterium bifidum CUL20 and Bifidobacterium animalis subsp. lactis CUL34) at a total of 12.5 billion cfu and 50 mg vitamin C per tablet.
2. The placebo intervention contains the same ingredients without the probiotic consortium and Vitamin C actives and is identical in appearance to the active intervention.

Intervention type



Drug names

Primary outcome measure

The incidence and duration of URTI assessed using daily health diaries completed by parents/guardians over the six month study period

Secondary outcome measures

Over the six month study period:
1. Absence from preschool or primary school assessed using the daily health diaries completed by parents/guardians
2. Antibiotic prescriptions assessed using the daily health diaries completed by parents/guardians and paediatric physician’s records
3. Lower respiratory tract infections assessed using the paediatric physician’s records
4. Gastrointestinal symptoms, such as change in bowel habits, vomiting, stomach ache, assessed using the daily health diaries completed by parents/guardians
5. Microbiota composition, diversity and functionality assessed using next-generation sequencing, traditional culture methods and 1H NMR spectroscopic analysis. The faecal sample collection is from a single centre and on a voluntary basis at day 0 (baseline) and 6 months

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Healthy children of either sex attending preschool facilities (3-6 years old) or primary school (7-10 years old)
2. Children with no flu vaccination
3. Parents/guardian who are willing to give written informed consent
4. Children who are willing to avoid any other probiotic supplements or dairy probiotic products (probiotic yoghurt, acidophilus milk, kefir etc.) for the duration of the project
5. Provision of faecal sample at the beginning and the end of the study will be voluntary

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

1. Parents are unable/unwilling to give written informed consent
2. Taking regularly any dairy probiotic product (probiotic yoghurt, acidophilus milk, kefir, etc)
3. Taking regularly any probiotic and prebiotic supplements
4. Taking medication to stimulate the immune system
5. Taking regularly Vitamin C
6. Sensitive to xylitol/sorbitol

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

JuvenaliaA, s.r.o, Children’s Health Centre, Dunajska Streda, Slovakia
Veľkoblahovská 23
Dunajská Streda

Trial participating centre

Children and adolescents health practice, DFNsP, Bratislava, Slovakia
Limbová 1

Trial participating centre

Meditrix s.r.o., Bratislava, Slovakia
Ružinovská 10

Trial participating centre

GAMI-med, s.r.o, General Practice for children and adolescents, Bratislava, Slovakia
Šustekova 2

Sponsor information


Cultech Ltd

Sponsor details

Unit 2 Christchurch Road
Baglan Industrial Park
Port Talbot
SA12 7BZ
United Kingdom
01639 825100

Sponsor type




Funder type


Funder name

Cultech Ltd

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Results will be published in a peer-reviewed scientific journal.

IPD sharing statement
The datasets generated and/or analysed during the current study during this study will be included in the subsequent results publication.

Intention to publish date


Participant level data


Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

10/11/2020: The intention to publish date was changed from 01/11/2020 to 01/02/2021. 10/07/2020: The intention to publish date was changed from 31/01/2020 to 01/11/2020. 17/09/2019: Trial's existence confirmed by ethics committee.