Cohort profile: the China Ageing REespiratory infections Study (CARES), a prospective cohort study in older adults in Eastern China

A(H2N2) and A(H3N2) influenza pandemics elicited durable cross-reactive and protective antibodies against avian N2 neuraminidases

Human cases of avian influenza virus (AIV) infections are associated with an age-specific disease burden. As the influenza virus N2 neuraminidase (NA) gene was introduced from avian sources during the 1957 pandemic, we investigate the reactivity of N2 antibodies against A(H9N2) AIVs. Serosurvey of healthy individuals reveal the highest rates of AIV N2 antibodies in individuals aged ≥65 years. Exposure to the 1968 pandemic N2, but not recent N2, protected against A(H9N2) AIV challenge in female mice. In some older adults, infection with contemporary A(H3N2) virus could recall cross-reactive AIV NA antibodies, showing discernable human- or avian-NA type reactivity. Individuals born before 1957 have higher anti-AIV N2 titers compared to those born between 1957 and 1968. The anti-AIV N2 antibodies titers correlate with antibody titers to the 1957 N2, suggesting that exposure to the A(H2N2) virus contribute to this reactivity. These findings underscore the critical role of neuraminidase immunity in zoonotic and pandemic influenza risk assessment.

Cohort profile: Indian Network of Population-Based Surveillance Platforms for Influenza and Other Respiratory Viruses among the Elderly (INSPIRE)

PURPOSE

We describe here a multicentric community-dwelling cohort of older adults (>60 years of age) established to estimate incidence, study risk factors, healthcare utilisation and economic burden associated with influenza and respiratory syncytial virus (RSV) in India.

PARTICIPANTS

The four sites of this cohort are in northern (Ballabgarh), southern (Chennai), eastern (Kolkata) and western (Pune) parts of India. We enrolled 5336 participants across 4220 households and began surveillance in July 2018 for viral respiratory infections with additional participants enrolled annually. Trained field workers collected data about individual-level and household-level risk factors at enrolment and quarterly assessed frailty and grip strength. Trained nurses surveilled weekly to identify acute respiratory infections (ARI) and clinically assessed individuals to diagnose acute lower respiratory infection (ALRI) as per protocol. Nasal and oropharyngeal swabs are collected from all ALRI cases and one-fifth of the other ARI cases for laboratory testing. Cost data of the episode are collected using the WHO approach for estimating the economic burden of seasonal influenza. Handheld tablets with Open Data Kit platform were used for data collection.

FINDINGS TO DATE

The attrition of 352 participants due to migration and deaths was offset by enrolling 680 new entrants in the second year. All four sites reported negligible influenza vaccination uptake (0.1%-0.4%), low health insurance coverage (0.4%-22%) and high tobacco use (19%-52%). Ballabgarh had the highest proportion (54.4%) of households in the richest wealth quintile, but reported high solid fuel use (92%). Frailty levels were highest in Kolkata (11.3%) and lowest in Pune (6.8%). The Chennai cohort had highest self-reported morbidity (90.1%).

FUTURE PLANS

The findings of this cohort will be used to inform prioritisation of strategies for influenza and RSV control for older adults in India. We also plan to conduct epidemiological studies of SARS-CoV-2 using this platform.

Acute Neurologic Manifestations of Respiratory Viruses

PURPOSE OF REVIEW

Understanding the pathophysiology of COVID-19 and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that causes the disease has demonstrated the complexity of acute respiratory viruses that can cause neurologic manifestations. This article describes the most common respiratory viruses that have neurologic manifestations, with a focus on SARS-CoV-2 and COVID-19.

RECENT FINDINGS

In vitro and in vivo studies have better elucidated the neurotropism of various respiratory viruses. Understanding host cell receptors that mediate viral binding and entry not only demonstrates how viruses enter host cells but also provides possible mechanisms for therapeutic interventions. Elucidation of SARS-CoV-2 binding and fusion with host cells expressing the angiotensin-converting enzyme 2 (ACE2) receptor may also provide greater insights into its systemic and neurologic sequelae. Respiratory virus neurotropism and collateral injury due to concurrent inflammatory cascades result in various neurologic pathologies, including Guillain-Barré syndrome, encephalopathy, encephalitis, ischemic stroke, intracerebral hemorrhage, and seizures.

SUMMARY

Numerous respiratory viruses can infect the cells of the peripheral and central nervous systems, elicit inflammatory cascades, and directly and indirectly cause various neurologic manifestations. Patients with neurologic manifestations from respiratory viruses are often critically ill and require mechanical ventilation. Neurologists and neurointensivists should be familiar with the common neurologic manifestations of respiratory viruses and the unique and still-evolving sequelae associated with COVID-19.

Human post-infection serological response to the spike and nucleocapsid proteins of SARS-CoV-2

To inform seroepidemiological studies, we characterized the IgG‐ responses in COVID‐19 patients against the two major SARS‐CoV‐2 viral proteins, spike (S) and nucleocapsid (N). We tested 70 COVID‐19 sera collected up to 85 days post‐symptom onset and 230 non‐COVID‐19 sera, including 27 SARS sera from 2003. Although the average SARS‐CoV‐2 S and N‐IgG titers were comparable, N‐responses were more variable among individuals. S‐ and N‐assay specificity tested with non‐COVID‐19 sera were comparable at 97.5% and 97.0%, respectively. Therefore, S will make a better target due to its lower cross‐reactive potential and its' more consistent frequency of detection compared to N.

Comparison of alternative full and brief versions of functional status scales among older adults in China

BACKGROUND

Brief assessments of functional status for community-dwelling older adults are needed given expanded interest in the measurement of functional decline.

METHODS

As part of a 2015 prospective cohort study of older adults aged 60-89 years in Jiangsu Province, China, 1506 participants were randomly assigned to two groups; each group was administered one of two alternative 20-item versions of a scale to assess activities of daily living (ADL) and instrumental activities of daily living (IADL) drawn from multiple commonly-used scales. One version asked if they required help to perform activities (ADL-IADL-HELP-20), while the other version provided additional response options if activities could be done alone but with difficulty (ADL-IADL-DIFFICULTY-20). Item responses to both versions were compared using the binomial test for differences in proportion (with Wald 95% confidence interval [CI]). A brief 9-item scale (ADL-IADL-DIFFICULTY-9) was developed favoring items identified as difficult or requiring help by ≥4%, with low redundancy and/or residual correlations, and with significant correlations with age and other health indicators. We repeated assessment of the measurement properties of the brief scale in two subsequent samples of older adults in Hong Kong in 2016 (aged 70-79 years; n = 404) and 2017 (aged 65-82 years; n = 1854).

RESULTS

Asking if an activity can be done alone but with difficulty increased the proportion of participants reporting restriction on 9 of 20 items, for which 95% CI for difference scores did not overlap with zero; the proportion with at least one limitation increased from 28.6% to 34.2% or an absolute increase of 5.6% (95% CI = 0.9-10.3%), which was a relative increase of 19.6%. The brief ADL-IADL-DIFFICULTY-9 maintained excellent internal consistency (α = 0.93) and had similar ceiling effect (68.1%), invariant item ordering (H trans = .41; medium), and correlations with age and other health measures compared with the 20-item version. The brief scale performed similarly when subsequently administered to older adults in Hong Kong.

CONCLUSIONS

Asking if tasks can be done alone but with difficulty can modestly reduce ceiling effects. It's possible that the length of commonly-used scales can be reduced by over half if researchers are primarily interested in a summed indicator rather than an inventory of specific types of deficits.

The Hurdles From Bench to Bedside in the Realization and Implementation of a Universal Influenza Vaccine

Influenza viruses circulate worldwide causing annual epidemics that have a substantial impact on public health. This is despite vaccines being in use for over 70 years and currently being administered to around 500 million people each year. Improvements in vaccine design are needed to increase the strength, breadth, and duration of immunity against diverse strains that circulate during regular epidemics, occasional pandemics, and from animal reservoirs. Universal vaccine strategies that target more conserved regions of the virus, such as the hemagglutinin (HA)-stalk, or recruit other cellular responses, such as T cells and NK cells, have the potential to provide broader immunity. Many pre-pandemic vaccines in clinical development do not utilize new vaccine platforms but use "tried and true" recombinant HA protein or inactivated virus strategies despite substantial leaps in fundamental research on universal vaccines. Significant hurdles exist for universal vaccine development from bench to bedside, so that promising preclinical data is not yet translating to human clinical trials. Few studies have assessed immune correlates derived from asymptomatic influenza virus infections, due to the scale of a study required to identity these cases. The realization and implementation of a universal influenza vaccine requires identification and standardization of set points of protective immune correlates, and consideration of dosage schedule to maximize vaccine uptake.

Knowledge, attitudes and practices related to the influenza virus and vaccine among older adults in Eastern China

BACKGROUND

This study aims to assess the association between socio-demographic and health characteristics of older adults in Eastern China and knowledge, attitudes, and practices (KAP) about the influenza virus and vaccine.

METHODS

A prospective cohort of 1506 older adults (aged ≥60 years) was enrolled from November to December 2015 in Jiangsu Province. We examined the association between demographics, health and functional status, and cognitive impairment at enrollment with awareness of influenza virus and vaccine and KAP items focused on five Health Belief Model domains. At a 12-month follow-up interview we assessed change in awareness and readiness to be vaccinated.

RESULTS

One in five older adults was aware of the influenza virus (21%) or vaccine (20%); even fewer reported having at least "a little" knowledge of the virus and vaccine (7% and 4%, respectively); less than 1% reported ever receiving an influenza vaccine. Retirement, higher education and income, and normal cognitive status were consistently associated with both awareness and knowledge of influenza virus. The odds of having at least "a little" knowledge of the vaccine was 2.9-fold (95% CI = 1.6-5.3) higher among older adults with at least some secondary schooling. Among the 108 with knowledge of the virus, 55% said they "worry about getting the flu this season." Among the 73 with knowledge of the vaccine, 92% believed the vaccine was at least somewhat effective and less than half (43%) thought that influenza vaccination was safe. At a 12-month follow-up interview, 33% (442/1333) increased from no knowledge to at least "a little".

CONCLUSIONS

If and when influenza vaccines become widely available to older adults in China, our results indicate that influenza vaccination campaigns with basic information on the virus and vaccine could be beneficial for all older adults, especially those with less education and/or more cognitive impairment.