Advances in respiratory virus therapeutics - A meeting report from the 6th isirv Antiviral Group conference

Critical care management of adults with community-acquired severe respiratory viral infection

With the expanding use of molecular assays, viral pathogens are increasingly recognized among critically ill adult patients with community-acquired severe respiratory illness; studies have detected respiratory viral infections (RVIs) in 17-53% of such patients. In addition, novel pathogens including zoonotic coronaviruses like the agents causing Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and the 2019 novel coronavirus (2019 nCoV) are still being identified. Patients with severe RVIs requiring ICU care present typically with hypoxemic respiratory failure. Oseltamivir is the most widely used neuraminidase inhibitor for treatment of influenza; data suggest that early use is associated with reduced mortality in critically ill patients with influenza. At present, there are no antiviral therapies of proven efficacy for other severe RVIs. Several adjunctive pharmacologic interventions have been studied for their immunomodulatory effects, including macrolides, corticosteroids, cyclooxygenase-2 inhibitors, sirolimus, statins, anti-influenza immune plasma, and vitamin C, but none is recommended at present in severe RVIs. Evidence-based supportive care is the mainstay for management of severe respiratory viral infection. Non-invasive ventilation in patients with severe RVI causing acute hypoxemic respiratory failure and pneumonia is associated with a high likelihood of transition to invasive ventilation. Limited existing knowledge highlights the need for data regarding supportive care and adjunctive pharmacologic therapy that is specific for critically ill patients with severe RVI. There is a need for more pragmatic and efficient designs to test different therapeutics both individually and in combination.

Involvement of the Nervous System in SARS-CoV-2 Infection

As a severe and highly contagious infectious disease, coronavirus disease 2019 (COVID-19) has caused a global pandemic. Several case reports have demonstrated that the respiratory system is the main target in patients with COVID-19, but the disease is not limited to the respiratory system. Case analysis indicated that the nervous system can be invaded by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and that 36.4% of COVID-19 patients had neurological symptoms. Importantly, the involvement of the CNS may be associated with poor prognosis and disease worsening. Here, we discussed the symptoms and evidence of nervous system involvement (directly and indirectly) caused by SARS-CoV-2 infection and possible mechanisms. CNS symptoms could be a potential indicator of poor prognosis; therefore, the prevention and treatment of CNS symptoms are also crucial for the recovery of COVID-19 patients.

Anti-influenza immune plasma for the treatment of patients with severe influenza A: a randomised, double-blind, phase 3 trial

BACKGROUND

Infection with influenza virus causes substantial morbidity and mortality globally, although antiviral treatments are available. Previous studies have suggested that anti-influenza immune plasma could be beneficial as treatment, but they were not designed as randomised, blinded, placebo-controlled trials. Therefore, we aimed to prospectively evaluate the clinical efficacy of high-titre immune plasma compared with standard low-titre plasma to improve outcomes in patients with severe influenza A infection.

METHODS

We did this randomised, double-blind, phase 3 trial at 41 US medical centres to assess the efficacy of high-titre anti-influenza plasma (haemagglutination inhibition antibody titre ≥1:80) compared with low-titre plasma (≤1:10). Children and adults with PCR-confirmed influenza A infection, a National Early Warning score of 3 or greater, and onset of illness within 6 days before randomisation were eligible. Patients were randomly assigned (2:1) using an interactive web response system to receive either two units (or paediatric equivalent) of high-titre plasma (high-titre group) or low-titre plasma (low-titre group), and were followed up for 28 days from randomisation. High-titre and low-titre plasma had the same appearance. Randomisation was stratified by severity (in intensive care unit, not in intensive care but requiring supplemental oxygen, or not in intensive care and not requiring supplemental oxygen) and age (<18 years and ≥18 years). All participants, site staff, and the study team were masked to treatment allocation until after the final database lock. The primary endpoint was clinical status assessed by a six-point ordinal scale on day 7 (death, in intensive care, hospitalised but requiring supplemental oxygen, hospitalised not requiring supplemental oxygen, discharged but unable to resume normal activities, and discharged with full resumption of normal activities) analysed in a proportional odds model (an odds ratio [OR] >1 indicates improvement in clinical status across all categories for the high-titre vs the low-titre group). The primary analysis was done in the intention-to-treat population, excluding two participants who did not receive plasma. This trial is registered with ClinicalTrials.gov, NCT02572817.

FINDINGS

Participants were recruited between Jan 26, 2016, and April 19, 2018. Of 200 participants enrolled (177 adults and 23 children), 140 met the criteria for randomisation and were assigned to the high-titre group (n=92) or to the control low-titre group (n=48). One participant from each group did not receive plasma. At baseline, 60 (43%) of 138 participants were in intensive care and 55 (71%) of 78 participants who were not in intensive care required oxygen. 93% of planned plasma infusions were completed. The study was terminated in July, 2018, when independent efficacy analysis showed low conditional power to detect an effect of high-titre plasma even if full accrual (150 participants) was achieved. The proportional OR for improved clinical status on day 7 was 1·22 (95% CI 0·65-2·29, p=0·54). 47 (34%) of 138 participants experienced 88 serious adverse events: 32 (35%) with 60 events in the high-titre group and 15 (32%) with 28 events in the low-titre group. The most common serious adverse events were acute respiratory distress syndrome (ARDS; four [4%] vs two [4%]), allergic transfusion reactions (two [2%] vs two [4%]), and respiratory distress (three [3%] vs none). 65 (47%) participants experienced 183 adverse events: 42 (46%) with 126 events in the high-titre group and 23 (49%) with 57 events in the low-titre group. The most common adverse events were anaemia (four [3%] vs two [4%]) and ARDS (four [3%] vs three [5%]). Ten patients died during the study (six [7%] in the high-titre group vs four [9%] in the low-titre group, p=0·73). The most common cause of death was worsening of acute respiratory distress syndrome (two [2%] vs two [4%] patients).

INTERPRETATION

High-titre anti-influenza plasma conferred no significant benefit over non-immune plasma. Although our study did not have the precision to rule out a small, clinically relevant effect, the benefit is insufficient to justify the use of immune plasma for treating patients with severe influenza A.

FUNDING

National Institute of Allergy and Infectious Diseases of the National Institutes of Health (Bethesda, MD, USA).

Respiratory syncytial virus infection in adults

Human respiratory syncytial virus (RSV) belongs to the recently defined Pneumoviridae family, Orthopneumovirus genus. It is a negative sense, single stranded RNA virus that results in epidemics of respiratory infections that typically peak in the winter in temperate climates and during the rainy season in tropical climates. Generally, one of the two genotypes (A and B) predominates in a single season, alternating annually, although regional variation occurs. RSV is a cause of disease and death in children, older people, and immunocompromised patients, and its clinical effect on adults admitted to hospital is clarified with expanded use of multiplex molecular assays. Among adults, RSV produces a wide range of clinical symptoms including upper respiratory tract infections, severe lower respiratory tract infections, and exacerbations of underlying disease. Here we discuss the latest evidence on the burden of RSV related disease in adults, especially in those with immunocompromise or other comorbidities. We review current therapeutic and prevention options, as well as those in development.

New antibody-based prevention and treatment options for influenza

The antigenic diversity of human influenza viruses represents a challenge to the development of vaccines with durable immune protection. In addition, small molecule anti-influenza viral drugs can bring clinical relief to influenza patients but the emergence of drug resistant viruses can rapidly limit the effectiveness of such drugs. In the past decade, a number of human monoclonal antibodies have been described that can bind to and neutralize a broad range of influenza A and B viruses. Most of these monoclonal antibodies are directed against the viral hemagglutinin (HA) stalk and some have now been evaluated in early to mid-stage clinical trials. An important conclusion from these clinical studies is that hemagglutinin stalk-specific antibodies are safe and can reduce influenza symptoms. In addition, examples of bi- and multi-specific anti-influenza antibodies are discussed, although such antibodies have not yet progressed into clinical testing. In the future, antibody-based therapies might become part of our arsenal to prevent and treat influenza.