Epidemiology of COVID-19 outbreaks in aged care facilities during postvaccine period: a systematic review and meta-analysis.

OBJECTIVE: We aimed to define the epidemiology of COVID-19 outbreaks in aged care facilities (ACFs) during the postvaccine period, including vaccine effectiveness (VE) for this high-risk group. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Ovid Medline, Ovid Embase, Scopus, Web of Science and Cochrane databases were searched through 1 September 2023. ELIGIBILITY CRITERIA: Any original observational studies and trials reporting data on COVID-19 outbreaks among the partially/fully vaccinated residents from ACFs during or after the worldwide implementation of vaccine roll-out. DATA EXTRACTION AND SYNTHESIS: We estimated the attack rate, case fatality rate, mortality rate and VE during postvaccine period. Random effect model was adopted for meta-analysis. Quality assessment on all included studies was performed using the Meta Quality Appraisal Tool. RESULTS: 38 articles were included from 12 countries reporting 79 outbreaks with 1708 confirmed cases of COVID-19 from 78 ACFs. The pooled attack rate was 28% (95% CI 20% to 37%) among the fully vaccinated residents. Two-thirds (62.5%) of the index cases were unvaccinated healthcare professionals (eg, physicians, nurses) and caregivers. Unvaccinated residents had a significantly higher rates (12%) (95% CI 7% to 19%) of mortality compared with the vaccinated residents (2%) (95% CI% 1 to 4%) and the post-COVID-19 vaccine estimates for case fatality rate (13% vs 23%) and hospitalisation rate (17% vs 37%) were substantially lower. VE in preventing disease among residents in ACFs was 73% (95% CI 49% to 86). Overall, the included studies were heterogeneous in nature, however, the risk of bias was low to moderate. CONCLUSIONS: Our study reaffirmed the impact of vaccination as a key public health measure to minimise the burden of COVID-19 in ACFs. Facilities with higher crowding indexes should be prioritised for vaccination and should advocate for higher vaccination targets among staff and residents as a critical intervention strategy to minimise disease burden in this vulnerable population.

The relationship between hand hygiene and rates of acute respiratory infections among Umrah pilgrims: A pilot randomised controlled trial.

BACKGROUND: There is a lack of randomised controlled trials (RCTs) investigating the role of hand hygiene in preventing and containing acute respiratory infections (ARIs) in mass gatherings. In this pilot RCT, we assessed the feasibility of establishing a large-scale trial to explore the relationship between practising hand hygiene and rates of ARI in Umrah pilgrimage amidst the COVID-19 pandemic. METHODS: A parallel RCT was conducted in hotels in Makkah, Saudi Arabia, between April and July 2021. Domestic adult pilgrims who consented to participate were randomised 1:1 to the intervention group who received alcohol-based hand rub (ABHR) and instructions, or to the control group who did not receive ABHR or instructions but were free to use their own supplies. Pilgrims in both groups were then followed up for seven days for ARI symptoms. The primary outcome was the difference in the proportions of syndromic ARIs among pilgrims between the randomised groups. RESULTS: A total of 507 (control: intervention = 267: 240) participants aged between 18 and 75 (median 34) years were randomised; 61 participants were lost to follow-up or withdrew leaving 446 participants (control: intervention = 237:209) for the primary outcome analysis; of whom 10 (2.2 %) had developed at least one respiratory symptom, three (0.7 %) had 'possible ILI' and two (0.4 %) had 'possible COVID-19'. The analysis of the primary outcome found no evidence of difference in the proportions of ARIs between the randomised groups (odds ratio 1.1 [0.3-4.0] for intervention relative to control). CONCLUSION: This pilot trial suggests that conducting a future definitive RCT to assess the role of hand hygiene in the prevention of ARIs is feasible in Umrah setting amidst such a pandemic; however, outcomes from this trial are inconclusive, and such a study would need to be very large given the low rates of outcomes observed here. TRIAL REGISTRATION: This trial was registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN12622001287729), the full protocol can be accessed there.

Immunogenicity, safety, usability and acceptability of microarray patches for vaccination: a systematic review and meta-analysis.

BACKGROUND: Microarray patches (MAPs) deliver vaccines to the epidermis and the upper dermis, where abundant immune cells reside. There are several potential benefits to using MAPs, including reduced sharps risk, thermostability, no need for reconstitution, tolerability and self-administration. We aimed to explore and evaluate the immunogenicity, safety, usability and acceptability of MAPs for vaccination. METHODS: We searched CINAHL, Cochrane Library, Ovid Embase, Ovid MEDLINE and Web of Science from inception to January 2023. Eligibility criteria included all research studies in any language, which examined microarrays or microneedles intended or used for vaccination and explored immunogenicity, safety, usability or acceptability in their findings. Two reviewers conducted title and abstract screening, full-text reviewing and data extraction. RESULTS: Twenty-two studies were included (quantitative=15, qualitative=2 and mixed methods=5). The risk of bias was mostly low, with two studies at high risk of bias. Four clinical trials were included, three using influenza antigens and one with Japanese encephalitis delivered by MAP. A meta-analysis indicated similar or higher immunogenicity in influenza MAPs compared with needle and syringe (N&S) (standardised mean difference=10.80, 95% CI: 3.51 to 18.08, p<0.00001). There were no significant differences in immune cell function between MAPs and N&S. No serious adverse events were reported in MAPs. Erythema was more common after MAP application than N&S but was brief and well tolerated. Lower pain scores were usually reported after MAP application than N&S. Most studies found MAPs easy to use and highly acceptable among healthcare professionals, laypeople and parents. CONCLUSION: MAPs for vaccination were safe and well tolerated and evoked similar or enhanced immunogenicity than N&S, but further research is needed. Vaccine uptake may be increased using MAPs due to less pain, enhanced thermostability, layperson and self-administration. MAPs could benefit at-risk groups and low and middle-income countries. PROSPERO REGISTRATION NUMBER: CRD42022323026.

Epidemiological Differences in Hajj-Acquired Airborne Infections in Pilgrims Arriving from Low and Middle-Income versus High-Income Countries: A Systematised Review.

This systematised review aims to compare the epidemiological patterns of Hajj-acquired airborne infections among pilgrims from low and middle-income countries (LMIC) versus those from high-income countries (HIC). A PubMed search was carried out for all published articles before February 2023, using a combination of MeSH terms and text words. The Newcastle-Ottawa Scale (NOS) was used to assess data quality. From a total of 453 titles identified, 58 studies were included in the review (LMIC = 32, and HIC = 26). In the pooled sample, there were 27,799 pilgrims aged 2 days to 105 years (male: female = 1.3:1) from LMIC and 70,865 pilgrims aged 2 months to 95 years (male: female = 1:1) from HIC. Pilgrims from both HIC and LMIC had viral and bacterial infections, but pilgrims from HIC tended to have higher attack rates of viral infections than their LMIC counterparts. However, the attack rates of bacterial infections were variable: for instance, pilgrims from LMIC seemed to have higher rates of meningococcal infections (0.015-82% in LMIC vs. 0.002-40% in HIC) based on the study population, but not Mycobacterium tuberculosis (0.7-20.3% in LMIC vs. 38% in HIC). Targeted measures are needed to prevent the spread of airborne infections at Hajj.

The effectiveness of vaccination for preventing hospitalisation with COVID-19 in regional Queensland: a data linkage study.

OBJECTIVE: To estimate the effectiveness of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for protecting people in a largely coronavirus disease 2019 (COVID-19)-naïve regional population from hospitalisation with symptomatic COVID-19. DESIGN: Retrospective cohort study; analysis of positive SARS-CoV-2 polymerase chain reaction (PCR) test results linked with Central Queensland hospitals admissions data and Australian Immunisation Register data. SETTING, PARTICIPANTS: Adult residents of Central Queensland, 1 January - 31 March 2022. MAIN OUTCOME MEASURES: Vaccine effectiveness (1 - relative risk of hospitalisation for vaccinated and unvaccinated people) with respect to protecting against hospitalisation with symptomatic COVID-19 after primary vaccination course only (two doses of an approved SARS-CoV-2 vaccine) and after a booster vaccine dose. RESULTS: Positive SARS-CoV-2 test results were recorded during 1 January - 31 March 2022 for 9682 adults, 7244 of whom had been vaccinated (75%); 5929 people were aged 40 years or younger (62%), 5180 were women (52%). Forty-seven people were admitted to hospital with COVID-19 (0.48%), four required intensive care (0.04%); there were no in-hospital deaths. Vaccine effectiveness was 69.9% (95% confidence interval [CI], 44.3-83.8%) for people who had received only a primary vaccination course and 81.8% (95% CI, 39.5-94.5%) for people who had also received a booster. Of the 665 Aboriginal and Torres Strait Islander adults with positive SARS-CoV-2 test results, 401 had been vaccinated (60%). Six Indigenous people were hospitalised with symptomatic COVID-19 (0.9%); vaccine effectiveness was 69.4% (95% CI, -56.5% to 95.8%) for Indigenous people who had received a primary vaccination course only or the primary course and a booster. CONCLUSION: The hospitalisation rate for Central Queensland people with PCR-confirmed Omicron variant SARS-CoV-2 infections during the first quarter of 2022 was low, indicating the protection afforded by vaccination and the value of booster vaccine doses.

Perceived facilitators and barriers to the uptake of the human papillomavirus (HPV) vaccine among adolescents of Arabic-speaking mothers in NSW, Australia: A qualitative study.

Background: Australia has a large immigrant population but there is little data regarding whether human papillomavirus (HPV) vaccination coverage in adolescents varies according to parents' cultural or ethnic background. This work aims to identify facilitators and barriers to HPV vaccination of adolescents as perceived by Arabic-speaking mothers in Western Sydney, South Western Sydney and Wollongong, NSW, Australia. Methods: A purposive sampling approach was applied to recruit mothers of adolescents from Arabic speaking backgrounds who had at least one child eligible for the HPV school-based vaccination program. Face-to-face semi-structured well as online interviews were conducted in Arabic between April 2021 and July 2021. The interviews were audio-recorded, transcribed, and translated into English and examined using thematic analysis. Results: Sixteen mothers of adolescents from Arabic backgrounds described facilitators and barriers to HPV vaccination. A) Facilitators of HPV vaccination included: knowledge of HPV disease, trust in the school vaccination program, opportunistic recommendations from healthcare workers, information from friends. B) Barriers to accessing HPV vaccination included communication gaps: breakdown in school-parent information flow, lack of access to the Arabic language version of the information sheet, mother - GP communication barriers, mother-child communication gap; and health system gaps: missed opportunities for vaccination. C) Mothers' suggestions to improve HPV vaccination acceptance: to involve religious and cultural leadership, encourage engagement with GPs, and provide school-based education for parents and students. Conclusion: Parents could benefit from assistance with HPV vaccination decision making. Interventions via schools, health professionals and religious and cultural organisations could play important roles in HPV vaccination acceptance for Arabic speaking immigrant families and in introducing their adolescent children to this vaccine.

Active prospective national surveillance for congenital and neonatal varicella in Australia shows potential prevention opportunities.

To compare the incidence and outcomes of congenital and neonatal varicella in Australia in the pre-vaccination (1995-1997) and post-vaccination era (after 2005 to November 2020), active prospective national surveillance for congenital varicella syndrome (CVS) and neonatal varicella infection (NVI) was conducted through the Australian Paediatric Surveillance Unit (APSU). Compared with 1995-1997, there was a 91.5% reduction in the incidence of CVS and a 91.3% reduction in the incidence of NVI in 2009-2020. However, almost half of the mothers in 2009-2020 were born overseas and came from countries without a vaccination program. Although there has been a substantial and sustained decrease in the reported incidence of CVS and NVI in Australia since 2006, congenital and neonatal varicella infections persist. Thus, there is an opportunity for targeted screening of varicella in young migrant, asylum seeker and refugee women at risk of varicella infection and prioritisation for vaccination to prevent CVS and NVI.

Health behaviors are largely not predictive of adverse events following influenza vaccination.

BACKGROUND: Identifying health behaviors associated with adverse events following immunization (AEFI) could identify intervention targets for AEFI prevention. METHODS: University employees receiving an influenza vaccination (n = 1301) completed a series of online surveys for health behaviors including sleep, exercise, dietary intake, and smoking habits, and emotional state (baseline), and for indications of AEFI (three days post-vaccination) and influenza-like illness (ILI) symptoms (fortnightly follow-up for 4 months). RESULTS: 29.9% of participants reported an AEFI and 46.0% reported experiencing ILI during follow-up. Multivariate logistic regression revealed usual sleep duration was associated with AEFI (odds ratio 1.20, 95% confidence interval 1.03-1.41), increasing with each hour of sleep. ILI was associated with reporting AEFI (1.70, 1.24-2.33), increasing BMI (1.03, 1.00-1.06) and survey response frequency (1.13, 1.04-1.22), and decreased with better usual sleep quality (0.96, 0.92-1.00) and with increasing age (0.98, 0.96-1.00). Sex stratification revealed no significant predictors of AEFI for either sex; in women, experiencing AEFI increased likelihood of ILI (1.88, 1.25-2.85) and in men, survey completion frequency increased ILI likelihood (1.19, 1.05-1.36). CONCLUSIONS: Our study suggests modifying health behaviors would not alter AEFI risk and reactogenicity may signal weaker immunogenicity but confirmation through objective measures is warranted.

Rapid on-site molecular Point of Care Testing during influenza outbreaks in aged care facilities improves antiviral use and reduces hospitalisation.

OBJECTIVE: Western Sydney Local Health District (WSLHD) measured the utility and validity of rapid molecular point-of-care testing (POCT) in aged care facilities (ACFs) experiencing influenza-like illness (ILI) outbreaks against routine laboratory testing. METHODS: A descriptive epidemiological study into 82 respiratory outbreaks reported across 63 ACFs within WSLHD supporting approximately 6,500 residents aged ≥65 years and staffed by ∼6,500 employees, from 1 August 2018 to 31 December 2019. RESULTS: WSLHD Public Health Unit performed on-site testing at 27 ACF outbreaks (34%), while 53(66%) ACFs conducted only routine laboratory testing. The Xpert®Xpress Flu/RSV molecular PCR provided a sensitivity and specificity of 100%. Those with on-site testing, antiviral prophylaxis was prescribed at 75% of facilities within 24 hours of testing, as opposed to 32% of those using laboratory testing (p<0.01). There were 24 of 181 ACF residents hospitalised in the POCT group compared to 76 of 357 in the laboratory-only group (OR=0.57; p=0.02). CONCLUSIONS: On-site ACF testing is reliable and practical for early identification of influenza, enabling timely use of antiviral treatment and prophylaxis, and was associated with decreased hospitalisation. PUBLIC HEALTH IMPLICATIONS: Enhanced respiratory surveillance and on-site testing should be strongly considered as part of routine management of respiratory outbreaks in ACFs and may reduce outbreak severity.

Australian Paediatric Surveillance Unit (APSU) Annual Surveillance Report 2021.

Abstract: The Australian Paediatric Surveillance Unit (APSU) has been conducting surveillance of rare communicable and non-communicable conditions in children since its inception in 1993. In this report, the results are described of surveillance of ten communicable diseases (and complications) for 2021, including the numbers of cases and incidence estimates; demographics; clinical features; and management and short-term outcomes. The included diseases are: acute flaccid paralysis (AFP); congenital cytomegalovirus (CMV); neonatal herpes simplex virus (HSV) infection; paediatric human immunodeficiency virus (HIV) infection; perinatal exposure to HIV; severe complications from influenza; juvenile-onset respiratory papillomatosis (JoRRP); congenital rubella syndrome; congenital varicella syndrome; and neonatal varicella infection. In 2021, cases of JoRRP were reported to the APSU for the first time since 2017, indicating potential gaps in HPV vaccination. AFP surveillance by APSU again contributed to Australia achieving a minimum target incidence of one AFP case per 100,000 children aged < 15 years. There were no cases of children with severe complications of influenza. No cases of varicella or congenital rubella were reported; however, at-risk populations, especially young migrant and refugee women from countries without universal vaccination programs, need to be screened and prioritised for vaccination prior to pregnancy. Cases of perinatal exposure to HIV continue to increase; however, the rate of mother-to-child-transmission remains at low levels due to the use of effective intervention strategies. Case numbers of congenital CMV and neonatal HSV remain steady in the absence of vaccines, prompting the need for greater awareness and education, with recent calls for target screening of at-risk infants for congenital CMV.

Severe Influenza-Associated Neurological Disease in Australian Children: Seasonal Population-Based Surveillance 2008-2018.

BACKGROUND: Influenza-associated neurological disease (IAND) is uncommon but can result in death or neurological morbidity in children. We aimed to describe the incidence, risk factors, and outcome of children with IAND from seasonal influenza in Australia. METHODS: We analyzed national, population-based, surveillance data for children aged ≤ 14 years with severe influenza and neurological involvement, over 11 Australian influenza seasons, 2008-2018, by the Australian Paediatric Surveillance Unit. RESULTS: There were 633 laboratory-confirmed cases of severe influenza reported. Of these, 165 (26%) had IAND. The average annual incidence for IAND was 3.39 per million children aged ≤ 14 years. Compared to cases without neurological complications, those with IAND were more likely to have a pre-existing neurological disease (odds ratio [OR] 3.03, P < .001), but most children with IAND did not (n = 135, 82%). Children with IAND were more likely to receive antivirals (OR 1.80, P = .002), require intensive care (OR 1.79, P = .001), require ventilation (OR 1.99; P = .001), and die (OR 2.83, P = .004). CONCLUSIONS: IAND is a preventable cause of mortality, predominantly in otherwise well children. Incidence estimates validate previous sentinel site estimates from Australia. IAND accounted for a quarter of all severe influenza, is associated with intensive care unit admission, and accounted for half of all influenza deaths.

Low Prevalence of Syndromic Respiratory Tract Infections among Returning Hajj Pilgrims Amidst the COVID-19 Pandemic: A Post-Hajj Survey.

This study estimates the point prevalence of symptomatic respiratory tract infections (RTIs) among returned Hajj pilgrims and their contacts in 2021. Using the computer-assisted telephone interview (CATI) technique, domestic pilgrims were invited to participate in this cross-sectional survey two weeks after their home return from Hajj. Of 600 pilgrims approached, 79.3% agreed to participate and completed the survey. Syndromic definitions were used to clinically diagnose possible influenza-like illnesses (ILI) and COVID-19. Median with range was applied to summarise the continuous data, and frequencies and proportions were used to present the categorical variables. Simple logistic regression was carried out to assess the correlations of potential factors with the prevalence of RTIs. The majority of pilgrims (88.7%) reported receiving at least two doses of the COVID-19 vaccine before Hajj. Eleven (2.3%) pilgrims reported respiratory symptoms with the estimated prevalence of possible ILI being 0.2%, and of possible COVID-19 being 0.4%. Among those who were symptomatic, five (45.5%) reported that one or more of their close contacts had developed similar RTI symptoms after the pilgrims' home return. The prevalence of RTIs among pilgrims who returned home after attending the Hajj 2021 was lower compared with those reported in the pre-pandemic studies; however, the risk of spread of infection among contacts following Hajj is still a concern.

Outbreaks of Human Metapneumovirus in Western Sydney Aged-Care Facilities in 2018.

Background: Human metapneumovirus (hMPV), first described in 2001, is a cause of acute respiratory tract infection in the elderly, with symptoms ranging from mild to severe, including pneumonia, but outbreaks are rarely described. Methods: Between 1 July and 31 December 2018, there were three outbreaks of Influenza-like Illness (ILI) where hMPV was the primary pathogen observed, among 64 aged-care facilities (ACFs) in Western Sydney. These outbreaks were investigated by the Western Sydney Local Health District (WSLHD) Public Health Unit (PHU); multiplex polymerase chain reaction (PCR) testing was performed on nasopharyngeal swabs collected by the ACF. Results: hMPV was the main causative pathogen in three outbreaks (27, 28, and 15 symptomatic cases, respectively) in late winter and early spring. Fifty-five residents and 15 staff cases (70 total cases) were identified; hMPV was detected in 12 of 63 specimens submitted. Of the cases in residents, eight were hospitalised (8/63; 15%), including five with confirmed hMPV and a further one epidemiologically linked to a positive case. Six residents died (6/63; 11%) during the hMPV outbreaks; four of these had laboratory-confirmed hMPV, with a further case epidemiologically linked to a hMPV case, with a primary diagnosis of pneumonia/viral pneumonia. The sixth death was not epidemiologically linked, nor did this case exhibit any respiratory symptoms during the outbreak; however, it was reported in line with public health guidelines. Conclusion: A major challenge in 2018 was the incompleteness of testing for, and awareness of, hMPV as a viral cause of ILI by facilities, laboratories, and emergency departments, which generally opted for rapid testing for influenza and RSV only. There is no licensed vaccine or approved treatment for hMPV, so efficient infection control measures are most important.

The role of chronic disease in the disparity of influenza incidence and severity between indigenous and non-indigenous Australian peoples during the 2009 influenza pandemic.

BACKGROUND: The 2009 H1N1 influenza pandemic (influenza A(H1N1)pdm09) disproportionately impacted Indigenous peoples. Indigenous Australians are also affected by a health gap in chronic disease prevalence. We hypothesised that the disparity in influenza incidence and severity was accounted for by higher chronic disease prevalence. METHODS: We analysed influenza data from Western Australia, South Australia, the Northern Territory, and Queensland. We calculated population prevalence of chronic diseases in Indigenous and non-Indigenous Australian populations using nationally-collected health survey data. We compared influenza case notifications, hospitalisations, intensive care admissions, and deaths reported amongst the total population of Indigenous and non-Indigenous Australians ≥ 15 years. We accessed age-specific influenza data reported to the Australian Department of Health during the 2009 'swine flu' pandemic, stratified by Indigenous status and the presence of one of five chronic conditions: chronic lower respiratory conditions, diabetes mellitus, obesity, renal disease, and cardiac disease. We calculated age-standardised Indigenous: non-Indigenous rate ratios and confidence intervals. FINDINGS: Chronic diseases were more prevalent in Indigenous Australians. Rates of influenza diagnoses were higher in Indigenous Australians and more frequent across all indices of severity. In those with chronic conditions, Indigenous: non-Indigenous influenza notification rate ratios were no lower than in the total population; in many instances they were higher. Rate ratios remained above 1·0 at all levels of severity. However, once infected (reflected in notifications), there was no evidence of a further increase in risk of severe outcomes (hospitalisations, ICU admissions, deaths) amongst Indigenous Australians compared to non-Indigenous Australians with a chronic disease. INTERPRETATION: Higher rates of influenza infection was observed amongst those Indigenous compared to non-Indigenous Australians, and this difference was preserved amongst those with a chronic condition. However, there was no further increase in prevalence of more severe influenza outcomes amongst Indigenous Australians with a chronic condition. This suggests that the prevalence of chronic disease, rather than Indigenous status, affected influenza severity. Other factors may be important, including presence of multiple morbidities, as well as social and cultural determinants of health.

Physical activity and acute exercise benefit influenza vaccination response: A systematic review with individual participant data meta-analysis.

Whether the vaccine adjuvant potential of acute exercise is uniform among different populations, e.g., inactive persons, is unknown. This meta-analysis examines influenza vaccine antibody responses and the effect of physical activity, acute exercise, and their interaction. Inclusion criteria comprised randomized controlled trials with acute exercise intervention and influenza vaccination antibody measurements at baseline and 4-6 weeks, and participant baseline physical activity measurement; there were no exclusion criteria. Searching via six databases (Medline, Embase, CINAHL, Scopus, Web of Science, and Physiotherapy Evidence) and two clinical registries (WHO and NIH), nine studies were identified and assessed with the Cochrane revised risk-of-bias tool. Data analysis comprised one-stage random-effects generalized linear mixed-effects models with random intercept. Seven of nine identified studies, all of high risk of bias, provided data for 550 included participants. Clinical measures of antibody response tended to be higher in the acute-exercised participants compared to rested controls and physically active compared to inactive. Physical activity significantly increased H1 strain seroconversion (adjusted odds ratio (aOR) 1.69, 95%CI: 1.02-2.82) among all participants and titer response (aOR 1.20, 95%CI: 1.03-1.39) among the acute exercise group. Increasing age frequently reduced immunogenic responses whereas body mass index and sex had little-to-no effect. Adjuvant effects were more pronounced with interventions exercising the same arm in which the vaccination was administered. H1 response was increased by both physical activity and the acute exercise-physical activity interaction. Given the observed modifications by age and the subset analysis suggesting the benefit is more pronounced in older populations, future attention is due for acute exercise-PA interactions to impact vaccination response in the at-risk population of older adults. Further, we identify localized exercise as the likely most-effective protocol and encourage its use to augment the available evidence.

Syndromic surveillance of respiratory-tract infections and hand hygiene practice among pilgrims attended Hajj in 2021: a cohort study.

BACKGROUND: The risk of transmission of viral respiratory tract infections (RTIs) is high in mass gatherings including Hajj. This cohort study estimated the incidence of symptomatic RTIs and hand hygiene compliance with its impact among Hajj pilgrims during the COVID-19 pandemic. METHODS: During the week of Hajj rituals in 2021, domestic pilgrims were recruited by phone and asked to complete a baseline questionnaire. Pilgrims were followed up after seven days using a questionnaire about the development of symptoms, and practices of hand hygiene. Syndromic definitions were used to clinically diagnose 'possible' influenza-like illnesses (ILI) and COVID-19 infection. RESULTS: A total of 510 pilgrims aged between 18 and 69 (median of 50) years completed the questionnaire, 280 (54.9%) of whom were female, and all of them (except for one) were vaccinated against COVID-19 with at least one dose. The mean (± SD) of pilgrims' hand hygiene knowledge score (on a scale of 0 to 6) was 4.15 (± 1.22), and a higher level of knowledge was correlated with a higher frequency of handwashing using soap and water. Among those 445 pilgrims who completed the follow-up form, 21 (4.7%) developed one or more respiratory symptoms, of which sore throat and cough were the commonest (respectively 76.2% and 42.8%); 'possible ILI' and 'possible COVID-19' were present in 1.1% and 0.9% of pilgrims. Obesity was found to be a significant factor associated with the risk of developing RTIs (odds ratio = 4.45, 95% confidence interval 1.15-17.13). CONCLUSIONS: Hajj pilgrims are still at risk of respiratory infections. Further larger and controlled investigations are needed to assess the efficacy of hand hygiene during Hajj.