|Credit CDC PHIL|
While the number of mild and moderate H7N9 cases that recover are unknown, we know that roughly 40% of those patients who are sick enough to be hospitalized eventually succumb to their infection.
From time to time we get glimpses of their in-hospital course of treatment (see below), but seldom to we hear about their long-term recovery.
Given the severity of the illness, often requiring ventilation support, and the demographics of infection - skewed heavily towards older men, often with comorbidities (see A Look At The Demographics Of H7N9) - it would not be unexpected to find long-term sequelae.
Today we've a new study, published in Nature Scientific Reports, that follows the 2-year post-hospital recovery of 56 H7N9 cases in Zhejiang Province, China.
Researchers report a substantial number of patients continued to show reduced pulmonary function - and to report a reduced level of health-related quality of life (HRQoL) - at the end of that 24 month follow-up period.
Jiajia Chen, Jie Wu, Shaorui Hao, Meifang Yang, Xiaoqing Lu, Xiaoxiao Chen & Lanjuan Li
Scientific Reports 7, Article number: 17275 (2017)
Published online: 8 December 2017
Patients who survive influenza A (H7N9) virus infection are at risk of physical and psychological complications of lung injury and multi-organ dysfunction. However, there were no prospectively individualized assessments of physiological, functional and quality-of-life measures after hospital discharge. The current study aims to assess the main determinants of functional disability of these patients during the follow-up.
Fifty-six influenza A (H7N9) survivors were investigated during the 2-year after discharge from the hospital. Results show interstitial change and fibrosis on pulmonary imaging remained 6 months after hospital discharge. Both ventilation and diffusion dysfunction improved, but restrictive and obstructive patterns on ventilation function test persisted throughout the follow-up period. For patients with acute respiratory distress syndrome lung functions improved faster during the first six months.
Role-physical and Role-emotional domains in the 36-Item Short-Form Health Survey were worse than those of a sex- and age-matched general population group. The quality of life of survivors with ARDS was lower than those with no ARDS. Our findings suggest that pulmonary function and imaging findings improved during the first 6 months especially for those with ARDS, however long-term lung disability and psychological impairment in H7N9 survivors persisted at 2 years after discharge from the hospital.
During the spring of 2013, a novel avian-origin influenza virus emerged. This new virus had a genome similar phylogenetically to that of a chicken A(H7N9) virus isolated from an epidemiologically linked live poultry market1 and was thus identified as an avian (H7N9) virus1,2,3. H7N9 viruses can cause severe illnesses in persons with contact to poultry, including pneumonia and acute respiratory distress syndrome (ARDS) with high case fatality rates2,4.
As of August 31, 2016, a total of 795 laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus had been reported in China4. The infections were also detected in the travelers of Canada (two) and Malaysia (one) to China4. Although the clinical features of hospitalized patients with H7N9 virus infection are generally similar to those of patients with severe pandemic H1N15 or H5N1 virus infections6, the mortality rates of H7N9 and H5N1 have been reported to be 37.1% and 53.2%, respectively7, whereas that of H1N1 was < 1%5.
Patients who survive influenza A (H7N9) virus infection are at risk of physical and psychological complications of lung injury and multi-organ dysfunction. However, previous studies have not included prospectively individualized assessments of physiological, functional and quality-of-life measures after hospital discharge to assess the main determinants of functional disability. Therefore, the goal of this study was to assess the long-term changes in pulmonary function and quality of life among patients recovering from H7N9 infection.
In summary, long-term lung disability and psychological impairment in H7N9 survivors persisted at 2 years after discharge from the hospital. Pulmonary function and imaging findings improved during the first 6 months especially for those with ARDS.
Most survivors returned to work, but at the 2-year follow-up, more than half of survivors still had ventilation and blood-gas diffusion dysfunction. The H7N9 survivors had impaired HRQoL scores that were lower than those of a sex- and age-matched control population, and ARDS substantially influenced these scores.
The good news here - at least so far - is that H7N9 has not produced the kind of reports of severe neurological impairment that we've occasionally seen with H5N1 (see CJ ID & MM: Case Study Of A Neurotropic H5N1 Infection - Canada).
But even without that component, the potential impact of a prolonged, often incomplete, recovery on patients and their loved ones, and - in the event of a pandemic - to society in general, cannot be overstated.No matter how you slice it, should H7N9 ever acquire the ability to transmit efficiently from human-to-human, the world would be be facing a formidable public health threat.