Seroprevalence of H7N9 infection among humans: A systematic review and meta-analysis

Serological evidence of human infection with avian influenza A(H7N9) virus: a systematic review and meta-analysis

Background

The extent of human infections with avian influenza A(H7N9) virus, including mild and asymptomatic infections, is uncertain.

Methods

We performed a systematic review and meta-analysis of serosurveys for avian influenza A(H7N9) virus infections in humans published during 2013–2020. Three seropositive definitions were assessed to estimate pooled seroprevalence, seroconversion rate, and seroincidence by types of exposures. We applied a scoring system to assess the quality of included studies.

Results

Of 31 included studies, pooled seroprevalence of A(H7N9) virus antibodies from all participants was 0.02%, with poultry workers, close contacts, and general populations having seroprevalence of 0.1%, 0.2%, and 0.02%, respectively, based on the World Health Organization (WHO)—recommended definition. Although most infections were asymptomatic, evidence of infection was highest in poultry workers (5% seroconversion, 19.1% seroincidence per 100 person-years). Use of different virus clades did not significantly affect seroprevalence estimates. Most serological studies were of low to moderate quality and did not follow standardized seroepidemiological protocols or WHO-recommended laboratory methods.

Conclusions

Human infections with avian influenza A(H7N9) virus have been uncommon, especially for general populations. Workers with occupational exposures to poultry and close contacts of A(H7N9) human cases had low risks of infection.

Pain management during the withholding and withdrawal of life support in critically ill patients at the end-of-life: a systematic review and meta-analysis

Purpose

To review and summarize the most frequent medications and dosages used during withholding and withdrawal of life-prolonging measures in critically ill patients in the intensive care unit.

Methods

We searched PubMed, EMBASE, the Cochrane Database of Systematic Reviews, and the Virtual Health Library from inception through March 2019. We considered any study evaluating pharmaceutical interventions for pain management during the withholding or withdrawing of life support in adult critically ill patients at the end-of-life. Two independent investigators performed the screening and data extraction. We pooled data on utilization rate of analgesic and sedative drugs and summarized the dosing between the moment prior to withholding or withdrawal of life support and the moment before death.

Results

Thirteen studies met inclusion criteria. Studies were conducted in the United States (38%), Canada (31%), and the Netherlands (31%). Eleven studies were single-cohort and twelve had a Newcastle–Ottawa Scale score of less than 7. The mean age of the patients ranged from 59 to 71 years, 59–100% were mechanically ventilated, and 47–100% of the patients underwent life support withdrawal. The most commonly used opioid and sedative were morphine [utilization rate 60% (95% CI 48–71%)] and midazolam [utilization rate 28% (95% CI 23–32%)], respectively. Doses increased during the end-of-life process (pooled mean increase in the dose of morphine: 2.6 mg/h, 95% CI 1.2–4).

Conclusions

Pain control is centered on opioids and adjunctive benzodiazepines, with dosages exceeding those recommended by guidelines. Despite consistency among guidelines, there is significant heterogeneity among practices in end-of-life care.

Electronic supplementary material

The online version of this article (10.1007/s00134-020-06139-7) contains supplementary material, which is available to authorized users.

Travel health risk perceptions of Chinese international students in Australia - Implications for COVID-19

BACKGROUND

International students frequently return to their country of origin to visit friends and relatives (VFR), and are at increased risk of travel-associated infections. Little is known of their travel health seeking behaviours. China is the biggest source of international students studying in Australia and the unprecedented epidemic of COVID-19 in China makes this an important area of research.

METHODS

Focus groups of Chinese international students were conducted to explore travel health-related knowledge, attitudes and practices. Eligible participants were studying in Sydney, and had travelled to China and Hong Kong to visit friends and relatives in the preceding 18 months. A variety of topics were explored, using a focus group guide. Thematic analysis was undertaken on the transcripts using nVivo software. The list of codes and themes were not pre-determined but developed through content analysis.

RESULTS

Two focus groups were held with a total of 28 participants. Risk perception about VFR travel was generally low among Chinese international students. Pre-travel healthcare was not sought. Students strongly relied on the Internet, social media, parents and friends in China for travel health advice.

CONCLUSION

This research provides insights into Chinese international students as VFR travellers. It confirms students could be a risk population for importations of infections such as COVID-19 because of low risk perception and lack of seeking travel health advice. This can inform health promotion strategies for students.

Seroprevalence of H7N9 infection among humans: A systematic review and meta-analysis

In spring 2013, a novel avian-origin influenza A (H7N9) virus emerged in mainland China. The burden of H7N9 infection was estimated based on systematic review and meta-analysis. The systematic search for available literature was conducted using Chinese and English databases. We calculated the pooled seroprevalence of H7N9 infection and its 95% confidence interval by using Freeman-Tukey double arcsine transformation. Out of 16 890 records found using Chinese and English databases, 54 articles were included in the meta-analysis. These included studies of a total of 64 107 individuals. The pooled seroprevalence of H7N9 infection among humans was 0.122% (95% CI: 0.023, 0.275). In high-risk populations, the highest pooled seroprevalence was observed among close contacts (1.075%, 95% CI: 0.000, 4.357). The seroprevalence among general population was (0.077%, 95% CI: 0.011, 0.180). Our study discovered that asymptomatic infection of H7N9 virus did occur, even if the seroprevalence among humans was low.