Contamination and washing of cloth masks and risk of infection among hospital health workers in Vietnam: a post hoc analysis of a randomised controlled trial.

BACKGROUND: In a previous randomised controlled trial (RCT) in hospital healthcare workers (HCWs), cloth masks resulted in a higher risk of respiratory infections compared with medical masks. This was the only published RCT of cloth masks at the time of the COVID-19 pandemic. OBJECTIVE: To do a post hoc analysis of unpublished data on mask washing and mask contamination from the original RCT to further understand poor performance of the two-layered cotton cloth mask used by HCWs in that RCT. SETTING: 14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam. PARTICIPANTS: A subgroup of 607 HCWs aged ≥18 years working full time in selected high-risk wards, who used a two-layered cloth mask and were part of a randomised controlled clinical trial comparing medical masks and cloth masks. INTERVENTION: Washing method for cloth masks (self-washing or hospital laundry). A substudy of contamination of a sample of 15 cloth and medical masks was also conducted. OUTCOME MEASURE: Infection rate over 4 weeks of follow up and viral contamination of masks tested by multiplex PCR. RESULTS: Viral contamination with rhinovirus was identified on both used medical and cloth masks. Most HCW (77% of daily washing) self-washed their masks by hand. The risk of infection was more than double among HCW self-washing their masks compared with the hospital laundry (HR 2.04 (95% CI 1.03 to 4.00); p=0.04). There was no significant difference in infection between HCW who wore cloth masks washed in the hospital laundry compared with medical masks (p=0.5). CONCLUSIONS: Using self-reported method of washing, we showed double the risk of infection with seasonal respiratory viruses if masks were self-washed by hand by HCWs. The majority of HCWs in the study reported hand-washing their mask themselves. This could explain the poor performance of two layered cloth masks, if the self-washing was inadequate. Cloth masks washed in the hospital laundry were as protective as medical masks. Both cloth and medical masks were contaminated, but only cloth masks were reused in the study, reiterating the importance of daily washing of reusable cloth masks using proper method. A well-washed cloth mask can be as protective as a medical mask. TRIAL RESGISTRATION NUMBER: ACTRN12610000887077.

Trends in Socioeconomic Inequalities in the Use of Antenatal Care Services by Women Aged 15 to 49 Years in Vietnam.

Despite considerable variations in the use of antenatal care (ANC) services in Vietnam, limited information is available on socioeconomic inequalities concerning the use of ANC services. This study aimed to assess the trends and changes in socioeconomic inequalities in the use of ANC services by women aged 15 to 49 years in Vietnam from 2006 to 2014. We used data from the Multiple Indicator Cluster Survey conducted in 2006, 2011, and 2014. The percentage of women who received ANC services increased significantly from 26.5% in 2006 to 42.7% in 2011 and reached 56.6% in 2014. We found a decreasing trend in the concentration indices of the use of ANC services from 0.36 in 2006 to 0.19 in 2014. The common factors significantly associated with the higher percentage of the use of ANC services in 2006, 2011, and 2014 were women belonging to the Kinh and Hoa ethnic groups and belonging to wealthier groups. Our study showed a reduction in socioeconomic inequality in the use of ANC services between 2004 and 2014. However, significant inequalities still exist in the use of ANC services based on women's education, ethnicity, and economic status.

Compliance with the Use of Medical and Cloth Masks Among Healthcare Workers in Vietnam.

BACKGROUND: Masks are often worn in healthcare settings to prevent the spread of infection from healthcare workers (HCWs) to patients. Masks are also used to protect the employee from patient-generated infectious organisms but poor compliance can reduce efficacy. The aim of this study was to examine the factors influencing compliance with the use of medical and cloth masks amongst hospital HCWs. METHODS: HCWs compliance with the use of medical and cloth masks was measured over a 4-week period in a randomized controlled trial in Vietnam. HCWs were instructed to record their daily activities in diary cards. Demographic, clinical, and diary card data were used to determine the predictors of compliance and the relationship of compliance with infection outcomes. RESULTS: Compliance rates for both medical and cloth masks decreased during the 4 weeks: medical mask use decreased from 77 to 68% (P < 0.001) and cloth masks from 78 to 69% (P < 0.001). The presence of adverse events (adjusted RR 0.90, 95% CI 0.85-0.95), and performing aerosol-generating procedures (adjusted RR 0.78, 95% CI 0.73-0.82) were negatively associated with compliance, while contact with febrile respiratory illness patients was positively associated (adjusted RR 1.14, 95% CI 1.07-1.20). Being compliant with medical or cloth masks use (average use ≥70% of working time) was not associated with clinical respiratory illness, influenza-like illness, and laboratory-confirmed viral infection. CONCLUSION: Understanding the factors that affect compliance is important for the occupational health and safety of HCWs. New strategies and tools should be developed to increase compliance of HCWs. The presence of adverse events such as discomfort and breathing problems may be the main reasons for the low compliance with mask use and further studies should be conducted to improve the design/material of masks to improve comfort for the wearer.

Practices around the use of masks and respirators among hospital health care workers in 3 diverse populations.

A cross-sectional survey was conducted in 89 secondary- and tertiary-level hospitals in 3 countries, and samples of masks and respirators were also collected and examined. Results showed varied practices around the use of masks and respirators, which are probably influenced by the available resources and local recommendations. Nonstandardized practices are common in low-resource settings, which may be placing health care workers at risk.

A cluster randomised trial of cloth masks compared with medical masks in healthcare workers.

OBJECTIVE: The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks. SETTING: 14 secondary-level/tertiary-level hospitals in Hanoi, Vietnam. PARTICIPANTS: 1607 hospital HCWs aged ≥18 years working full-time in selected high-risk wards. INTERVENTION: Hospital wards were randomised to: medical masks, cloth masks or a control group (usual practice, which included mask wearing). Participants used the mask on every shift for 4 consecutive weeks. MAIN OUTCOME MEASURE: Clinical respiratory illness (CRI), influenza-like illness (ILI) and laboratory-confirmed respiratory virus infection. RESULTS: The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%. CONCLUSIONS: This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry: ACTRN12610000887077.

Examining the policies and guidelines around the use of masks and respirators by healthcare workers in China, Pakistan and Vietnam.

BACKGROUND: There is an ongoing debate regarding the type of respiratory protection that should be recommended for use for healthcare workers. MATERIALS AND METHODS: A cross-sectional survey was conducted in three countries: China, Pakistan and Vietnam. RESULTS: In China and Pakistan, the infection control guidelines were developed to be in line with the recommendations from the World Health Organization (WHO) and the Centers for Disease Control and Prevention, while in the Vietnamese guidelines the recommendations correspond with the WHO suggestions only. The guidelines from all three countries document the need for training and fit testing; however there is no system to monitor the training and fit testing programs. Across the three countries, there was some inconsistency with regard to the types of products (i.e. masks vs. respirators) recommended for influenza, severe acute respiratory syndrome (SARS) and tuberculosis. CONCLUSIONS: Available evidence should be examined and a comprehensive policy should be developed on the use of masks and respirators. The policy should address critical areas such as regulation, training, fit testing and reuse.

Seroprevalence survey of avian influenza A(H5N1) among live poultry market workers in northern Viet Nam, 2011.

OBJECTIVE: Highly pathogenic avian influenza A(H5N1) is endemic in poultry in Viet Nam. The country has experienced the third highest number of human infections with influenza A(H5N1) in the world. A study in Hanoi in 2001, before the epizootic that was identified in 2003, found influenza A(H5N1) specific antibodies in 4% of poultry market workers (PMWs). We conducted a seroprevalence survey to determine the seroprevalence of antibodies to influenza A(H5N1) among PMWs in Hanoi, Thaibinh and Thanhhoa provinces. METHODS: We selected PMWs from five markets, interviewed them and collected blood samples. These were then tested using a horse haemagglutination inhibition assay and a microneutralization assay with all three clades of influenza A(H5N1) viruses that have circulated in Viet Nam since 2004. RESULTS: The overall seroprevalence was 6.1% (95% confidence interval: 4.6-8.3). The highest proportion (7.2%) was found in PMWs in Hanoi, and the majority of seropositive subjects (70.3%) were slaughterers or sellers of poultry. DISCUSSION: The continued circulation and evolution of influenza A(H5N1) requires comprehensive surveillance of both human and animal sites throughout the country with follow-up studies on PMWs to estimate the risk of avian-human transmission of influenza A(H5N1) in Viet Nam.