Utilizing a multiplex PCR panel for respiratory pathogen may be a standard of care in a developed world, but it is not commonly utilized in low-middle income countries primarily because of high cost. Lack of good therapeutic interventions, evidence to de-escalate antibiotics and isolation infra-structure are some other reasons which make it cost-ineffective. COVID-19 pandemic has taught us many lessons, some of which include the importance of confirmation of clinical diagnosis and emphasis on infection control practices particularly in a dedicated oncology centre which deals with immunocompromised patients and cross-transmission can lead to devastating results. Due to these lessons, our institute strengthened its viral diagnostics, improved our antibiotic prescriptions patterns and came-up with more effective infection control practices.
There are multiple studies which have looked into the impact of diagnosing respiratory viral infections in oncology settings and have found varied results.7-9 Even IDSA guidelines on the use of same, fail to give a strong recommendation and only conclude that utilization of these molecular tests should be done in consideration with regards to hospital epidemiology and antibiotic stewardship. They also highlight lack of good randomized control trials which can answer these unmet needs.10
Our study found that in > 50% of patients, there was no specific antiviral added, that may be because of most patients were infected with RSV and Rhinovirus. Data of use of oral ribavirin for RSV is very heterogeneous and guidelines suggest its use in patients with high risk of progression to lower respiratory tract.11,12 Apart from influenza, and probably RSV, most other respiratory viruses do not have an approved antiviral agent as of now. This brings us to a point of therapeutic efficacy of doing the test (therapy change after testing), we do agree, addition of specific antiviral agent may not be possible in most the patients, but in a patient with respiratory symptoms and signs compatible with a respiratory viral infection and a positive respiratory viral result, it becomes easy to de-escalate antibiotics. In the era of multi-drug resistance gram negatives, management of febrile neutropenia has become even more challenging. Judicious use of antibiotics have shown good outcomes in oncology patients and most guidelines now recommend intervention by AMS team in management of febrile neutropenia.4,5 Multi-drug resistant gram negative is a major problem in India and oncology patients are most adversely affected by it. It is imperative that AMS is encouraged in India and this study makes an attempt towards that. Neutropenia was seen in more than half of our study population and still clinicians de-escalated antibiotics in close to 57% patients.
Change in infection control practices (shifting to transmission based precautions) is only possible after a diagnosis of respiratory infection has been made. Following good infection control practices is of utmost importance particularly in oncology settings as cross-transmission can lead to outbreaks with poor patient related outcomes. We were able to shift more than 75% of our patients to isolation rooms, providing a good example for hospital administrators to invest in good infection control infrastructure.
So, we feel if good antibiotic stewardship and infection control practices are put in place, then therapeutic efficacy of doing respiratory viral panels is very good particularly in immunocompromised hosts. Cost of antibiotic (median saving of 9000 INR per patient in our study) saved adds to the cost effectiveness of these tests. In a study done by Shinn et. al, they concluded that there was no difference in patient related outcomes in between patients with positive and negative viral panel results.9 High incidence of detecting rhinovirus (61%) may have been the reason for this outcome. In our study also, patients in whom antibiotics were not de-escalated (most commonly due to presence of bacterial co-infection) had high rates of rhinovirus detection (41.6% vs 3%; p=0.0002) and other patients related outcomes like length of stay, mortality and cost of antibiotics saved were badly affected (Table 2). Although human rhinovirus can cause severe pneumonia but it has also been reported as a nasal commensal13, so we recommend caution while interpreting reports with positive rhinovirus results.
Most of our cases were diagnosed in the July 2021-Octover 2021, this period of 4 months lead to over 68% of cases and also positive yield of doing the tests was also highest during this period (42.8%-66.6%). This may be because of heavy rains (monsoon) during this time of year, while this is in line with the national data, same was not observed in 2020 as pandemic led to a lockdown which may have affected the spread of respiratory viral infections.
Our study has many limitations. Firstly, it lacks a true comparator arm of patients in whom respiratory panel was negative, which could have given our study findings more credibility. Secondly, cost calculation of antibiotics is based on an assumption (7 days if virus test was not done). Lastly, it being a retrospective study, suffers from selection bias. Despite the limitations, our study gives a ‘real life’ insight into clinicians’ behavior after he/she finds a patient with proven respiratory viral infection in oncology settings. It also encourages antibiotic stewardship behavior among oncologists and promotes developing a culture for good infection control practices.