Efficacy of Nasal-sprayed Probiotics Containing Bacillus Subtilis and Bacillus Clausii (LiveSpo Navax) in the Supportive Treatment of Pneumonia in Children Infected With Viral Respiratory Syncytial Virus (RSV) and Bacterial Co-infections

Pneumonia is a common disease in children and one of the leading causes of death in young children, especially those under 1 year old, infants, and malnourished children. According to the World Health Organization (WHO), an estimated 12.9 million children die each year, with 4.3 million (33.4%) of those deaths attributed to pneumonia. In Vietnam, the mortality rate from pneumonia is highest among respiratory diseases (75%), compared to the overall mortality rate of 30-35%. Statistics show that on average, a child can experience 3 to 5 episodes of acute respiratory infections per year, including 1 to 2 episodes of pneumonia. Respiratory syncytial virus (RSV) infection and bacterial co-infection are the leading causes of severe pneumonia, and the rate of co-infection can range from 26.3% to 43.6%. Commonly associated bacteria include Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis. These bacteria can invade the lower respiratory tract and cause secondary infections, taking advantage of respiratory damage caused by RSV.

Currently, there is no vaccine or specific treatment available for children with RSV infection, and oxygen therapy is generally recommended for children experiencing respiratory failure. The use of the monoclonal antibody palivizumab and the antiviral nucleotide drug ribavirin is considered too expensive or risky for children and is only recommended for high-risk patients. Bacterial co-infections often require antibiotic treatment based on suspected or known pathogens, but the use of antibiotics has significant side effects and raises concerns about the development of resistance.

In recent years, probiotics have gained popularity as promising and safe candidates for preventive and supportive therapies in respiratory infections, aiming to aid in the treatment and reduction of respiratory tract infections. Probiotics, which are live microorganisms providing health benefits when consumed in adequate quantities, have traditionally been used to promote gut health. However, their potential role in respiratory infections, specifically RSV pneumonia, has not been extensively explored. Some studies suggest that certain strains of probiotics can directly interact with viruses, capturing them, inducing secondary growth to inhibit virus entry and growth, or modulating the immune response to reduce the risk of respiratory infections. Nevertheless, the impact of oral probiotics on the respiratory tract of infants is typically delayed (usually around 3-12 months) and primarily used for prophylaxis rather than as an adjunct to ARTI treatment. Hence, there is a need for alternative delivery routes of probiotics in ARTI treatment. In our recent study, we have proven that the nasal-spraying Bacillus spore liquid-form probiotics (LiveSpo Navax containing > 5 billion B. subtilis ANA4 and B. clausii ANA39/ 5 mL ampoule) can rapidly and effectively relieve symptoms of ARTIs due to respiratory syncytial virus (RSV) infection while exhibiting strong impacts in reducing the viral load and inflammation. This finding is the first demonstration that spraying probiotics directly into the nose could be a quick and effective symptomatic treatment for ARTIs.

In this following study, we conducted the double-blind, randomized, and controlled clinical trial to further examine the efficacy of LiveSpo Navax in supporting the treatment of children with severe pneumonia who require oxygen therapy due to RSV and bacterial co-infections.

Methods: A randomized, blind, and controlled clinical trial will be conducted. The parents of the patients will be required to provide various information about their children, including their full name, sex, age, obstetric history, vaccination history, and antibiotic use history. After obtaining informed consent, 100 patients with severe pneumonia due to RSV and bacterial co-infection will be randomly assigned to two groups (n = 50/group): the control group (referred to as the "Control" group) will receive 0.9% NaCl physiological saline, and the experimental group (referred to as the "Navax" group) will receive the probiotics LiveSpo Navax. The patients will be given a coded spray in the form of a blind sample to ensure the objectivity of the study. Clinical follow-up will be conducted for 7 days or more, and nasopharyngeal samples will be collected on day 0 and day 3 to evaluate potential reductions in viral load, co-infection bacteria, modulation of overreacted cytokine release, and the presence of probiotic spores in the patient's nasal mucosa.