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1.
JMIR Form Res ; 6(7): e34423, 2022 Jul 27.
Article in English | MEDLINE | ID: covidwho-1974493

ABSTRACT

BACKGROUND: There is growing evidence of the benefits of mobile health technology, which include symptom tracking apps for research, surveillance, and prevention. No study has yet addressed arbovirus symptom tracking in pregnancy. OBJECTIVE: This study aimed to evaluate the use of a smartphone app (ZIKApp) to self-report arbovirus symptoms and pregnancy complications and to assess compliance with daily symptom diaries during pregnancy in a cohort of women in an arbovirus-endemic, subtropical, middle-income country (Jamaica). METHODS: Pregnant women aged ≥16 years, having a smartphone, and planning on giving birth at the recruiting center were enrolled between February 2020 and July 2020. ZIKApp comprised a daily symptom diary based on algorithms to identify potential episodes of arbovirus infection and pregnancy complications. Sociodemographic, epidemiological, and obstetric information was collected at enrollment, with additional review of medical records, and users' perception was collected through an exit survey. Descriptive analyses and logistic regression analysis of possible factors associated with diary adherence were performed. RESULTS: Of the 173 women enrolled, 157 (90.8%) used ZIKApp for a median duration of 155 (IQR 127-173) days until pregnancy end, 6 (3.5%) used the app for <7 days, and 10 (5.8%) exited the study early. For each successive 30-day period from enrollment up to 150 days after enrollment, of these 157 women, 121 (77.1%) to 129 (82.2%) completed their daily symptom diary; 50 (31.8%) to 56 (35.7%) did so on the same day. Overall, 31.8% (50/157) of the women had good adherence to diary reporting (ie, they completed the task on the same day or 2 to 3 days later for ≥80% of the days enrolled). There were 3-fold higher odds of good adherence for participants aged >34 years versus those aged 25 to 29 years (adjusted odds ratio 3.14, 95% CI 1.10-8.98) and 2-fold higher odds for women with tertiary versus secondary education (adjusted odds ratio 2.26, 95% CI 1.06-4.83). Of the 161 women who ever made a diary entry, 5454 individual symptom reports were made (median 17 per woman; IQR 4-42; range 0-278); 9 (5.6%) women reported symptom combinations triggering a potential arbovirus episode (none had an adverse pregnancy outcome) and 55 (34.2%) reported painful uterine contractions or vaginal bleeding, mainly in the month before delivery. Overall, 51.8% (71/137) of the women rated the app as an excellent experience and were less likely to be poor diary adherers (P=.04) and 99.3% (138/139) reported that the app was easy to understand and use. CONCLUSIONS: This pilot found a high adherence to ZIKApp. It demonstrated the feasibility and usability of the app in an arbovirus-endemic region, supporting its future development to contribute to surveillance and diagnosis of arbovirus infections in pregnancy and to optimize maternal care.

2.
Eur J Epidemiol ; 37(5): 549-561, 2022 May.
Article in English | MEDLINE | ID: covidwho-1872578

ABSTRACT

Household transmission studies are useful to quantify SARS-CoV-2 transmission dynamics. We conducted a remote prospective household study to quantify transmission, and the effects of subject characteristics, household characteristics, and implemented infection control measures on transmission. Households with a laboratory-confirmed SARS-CoV-2 index case were enrolled < 48 h following test result. Follow-up included digitally daily symptom recording, regular nose-throat self-sampling and paired dried blood spots from all household members. Samples were tested for virus detection and SARS-CoV-2 antibodies. Secondary attack rates (SARs) and associated factors were estimated using logistic regression. In 276 households with 920 participants (276 index cases and 644 household members) daily symptom diaries and questionnaires were completed by 95%, and > 85% completed sample collection. 200 secondary SARS-CoV-2 infections were detected, yielding a household SAR of 45.7% (95% CI 39.7-51.7%) and per-person SAR of 32.6% (95%CI: 28.1-37.4%). 126 (63%) secondary cases were detected at enrollment. Mild (aRR = 0.57) and asymptomatic index cases (aRR = 0.29) were less likely to transmit SARS-CoV-2, compared to index cases with an acute respiratory illness (p = 0.03 for trend), and child index cases (< 12 years aRR = 0.60 and 12-18 years aRR = 0.85) compared to adults (p = 0.03 for trend). Infection control interventions in households had no significant effect on transmission. We found high SARs with the majority of transmissions occuring early after SARS-CoV-2 introduction into the household. This may explain the futile effect of implemented household measures. Age and symptom status of the index case influence secondary transmission. Remote, digitally-supported study designs with self-sampling are feasible for studying transmission under pandemic restrictions.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , COVID-19/epidemiology , Child , Family Characteristics , Humans , Pandemics/prevention & control , Prospective Studies
3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-336763

ABSTRACT

Background The Omicron variant has caused a new wave of SARS-CoV-2 infections worldwide. We explore crucial epidemiological parameters driving seasonal patterns of SARS-CoV-2 transmission in secondary schools and assess various infection control interventions over a 2.5-year time frame. Methods We developed an agent-based model parameterised with data from secondary schools in the Netherlands. We modelled the circulation of Omicron assuming a stable introduction rate of infections and accounted for uncertainty in epidemiological parameters describing virus transmissibility, susceptibility to reinfection, vaccine immune escape, and waning of sterilising immunity. We quantified the SARS-CoV-2 health burden defined as number of symptomatic student days. We further evaluated the cost-benefit (number of prevented infected students per absent student) for reactive quarantine interventions, regular screening using antigen tests, and annual booster vaccinations. Findings Durability of sterilising immunity is a key parameter that governs temporal SARS-CoV-2 transmission patterns in secondary schools. Our model predicts pronounced within-school seasonal patterns with dominant autumn outbreaks and smaller winter outbreaks and a maximum prevalence of 2.9% (95% CI: 0.7%-6.6%) symptomatic students during infection peaks. Regular screening and annual booster vaccination may reduce the health burden up to 15% (95% CI: 1.5%-27.8%) and have a higher cost-benefit ratio than reactive quarantine interventions (reduction: 4.3%;95% CI: -10.1% to 17.6%). Interpretation Immunity waning will determine the intensity and pattern of SARS-CoV-2 transmission in secondary schools in the medium-term future. If mitigation strategies are needed, screening and annual booster vaccination have the highest cost-benefit by reducing viral transmission with little educational disruption.

4.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-335269

ABSTRACT

Background In fall 2020 when schools in the Netherlands operated under a limited set of COVID-19 measures, we conducted outbreaks studies in four secondary schools to gain insight in the level of school transmission and the role of SARS-CoV-2 transmission via air and surfaces. Methods Outbreak studies were performed between 11 November and 15 December 2020 when the wild-type variant of SARS-CoV-2 was dominant. Clusters of SARS-CoV-2 infections within schools were identified through a prospective school surveillance study. All school contacts of cluster cases, irrespective of symptoms, were invited for PCR testing twice within 48 hrs and 4-7 days later. Combined NTS and saliva samples were collected at each time point along with data on recent exposure and symptoms. Surface and active air samples were collected in the school environment. All samples were PCR-tested and sequenced when possible. Results Out of 263 sampled school contacts, 24 tested SARS-CoV-2 positive (secondary attack rate 9.1%), of which 62% remained asymptomatic and 42% had a weakly positive test result. Phylogenetic analysis on 12 subjects from 2 schools indicated a cluster of 8 and 2 secondary cases, respectively, but also other distinct strains within outbreaks. Of 51 collected air and 53 surface samples, none were SARS-CoV-2 positive. Conclusion Our study confirmed within school SARS-CoV-2 transmission and substantial silent circulation, but also multiple introductions in some cases. Absence of air or surface contamination suggests environmental contamination is not widespread during school outbreaks.

5.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-330802

ABSTRACT

Objectives Primary care urgently needs treatments for COVID-19 patients because current options are limited, while these patients account for more than 90% of the people infected with SARS-CoV-2. Methods We evaluated a throat spray containing three Lactobacillaceae strains with broad antiviral properties in a randomized double-blind placebo-controlled trial. Seventy-eight eligible COVID-19 patients were randomized to verum (n=41) and placebo (n=37) within 96 hours of positive PCR-based SARS-CoV-2 diagnosis and per-protocol analysis was performed. Symptoms and severity were reported daily via an online diary. Combined nose-throat swabs and dried blood spots were collected at regular time points in the study. Results The daily reported symptoms were highly variable, with no added benefit for symptom resolution in the verum group. Specific monitoring of the applied lactobacilli strains showed that they were detectable via microbiome (27%) and qPCR analysis (82%) of the verum group. Their relative abundances were also negatively correlated with the acute symptom score. At the end of the trial, a trend towards lower SARS-CoV-2 viral loads was observed for the verum group (2/30, 6.7% positive) compared to the placebo group (7/27, 26% positive) (p = 0.07). Conclusions Despite a trend towards lower SARS-CoV-2 viral loads at the end of the trial and a negative correlation between relative abundances of the applied lactobacilli in the microbiome and acute symptoms, we did not observe a significant effect on overall symptom score for the verum group. This suggests that studies with earlier application of the spray in larger study populations are needed to further assess application potential.

6.
Clin Infect Dis ; 74(1): 66-73, 2022 01 07.
Article in English | MEDLINE | ID: covidwho-1633721

ABSTRACT

BACKGROUND: Understanding the role of children in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is critical to guide decision-making for schools in the pandemic. We aimed to describe the transmission of SARS-CoV-2 among children and adult staff in summer schools. METHODS: During July 2020, we prospectively recruited children and adult staff attending summer schools in Barcelona who had SARS-CoV-2 infection. Primary SARS-CoV-2 infections were identified through (1) a surveillance program in 22 summer schools of 1905 participants, involving weekly saliva sampling for SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) during 2-5 weeks; and (2) cases identified through the Catalonian Health Surveillance System of children diagnosed with SARS-CoV-2 infection by nasopharyngeal RT-PCR. All centers followed prevention protocols: bubble groups, handwashing, face masks, and conducting activities mostly outdoors. Contacts of a primary case within the same bubble were evaluated by nasopharyngeal RT-PCR. Secondary attack rates and the effective reproduction number in summer schools (Re*) were calculated. RESULTS: Among the >2000 repeatedly screened participants, 30 children and 9 adults were identified as primary cases. A total of 253 close contacts of these primary cases were studied (median, 9 [interquartile range, 5-10] for each primary case), among which 12 new cases (4.7%) were positive for SARS-CoV-2. The Re* was 0.3, whereas the contemporary rate in the general population from the same areas in Barcelona was 1.9. CONCLUSIONS: The transmission rate of SARS-CoV-2 infection among children attending school-like facilities under strict prevention measures was lower than that reported for the general population. This suggests that under preventive measures schools are unlikely amplifiers of SARS-CoV-2 transmission, supporting current recommendations for school opening.


Subject(s)
COVID-19 , Adult , Child , Humans , Pandemics , SARS-CoV-2 , Schools , Spain/epidemiology
7.
PLoS One ; 16(3): e0249391, 2021.
Article in English | MEDLINE | ID: covidwho-1167114

ABSTRACT

BACKGROUND: Households are important sites for transmission of SARS-CoV-2 and preventive measures are recommended. This study aimed to 1) investigate the impact of living with a person infected with SARS-CoV-2; 2) understand how household members implemented infection control recommendations in their home; and 3) identify the information and support needs of household members. METHODS: For this observational mixed-methods study, households with a person with confirmed SARS-CoV-2 infection were recruited via drive-through testing sites of Municipal Health Services, healthcare worker screening or hospital emergency visits in the University Medical Centre Utrecht, the Netherlands and via primary care physicians, hospital emergency visits or preoperative screening in the University Hospital of Antwerp, Belgium. We recorded household characteristics, including characteristics of all household members, together with their views on prevention measures. In a subset of households one adult household member was asked to participate in an interview investigating their views on preventive measures. Survey data were analysed using descriptive statistics and interview data by rapid framework analysis. A triangulation protocol was used to integrate findings. RESULTS: Thirty-four households (120 household members) were included in the quantitative survey. Twenty-two households were invited to be interviewed, of which 18 completed an interview (response 81.8%). Survey data showed that almost all households implemented some preventive measures, the use of face masks being least frequently reported. Measures taken depended on what was physically possible, the perceived severity of illness of the index patient and to what extent household members were willing to limit social interaction. Respondents did not believe in the effectiveness of wearing face masks within the house, and from the interviews this was explained by media coverage of face masks, impracticality and the stigma associated with wearing masks. Interviewees reported that quarantine had a high emotional burden and wished to have more information about the exact duration of quarantine, their own COVID-19 status, symptoms and when to seek medical help. CONCLUSION: People were willing to implement prevention measures, however actual adherence depended on perceived severity of illness and the perceived risk of becoming infected. Homes are social environments and recommendations for infection prevention should account for this context. Incorporating our findings into policy making could provide households with more relevant and actionable advice.


Subject(s)
COVID-19/epidemiology , Housing , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/prevention & control , COVID-19/transmission , Child , Child, Preschool , Female , Health Knowledge, Attitudes, Practice , Humans , Infant , Infant, Newborn , Male , Masks , Middle Aged , Quarantine , Young Adult
8.
Nat Commun ; 12(1): 1614, 2021 03 12.
Article in English | MEDLINE | ID: covidwho-1132071

ABSTRACT

The role of school-based contacts in the epidemiology of SARS-CoV-2 is incompletely understood. We use an age-structured transmission model fitted to age-specific seroprevalence and hospital admission data to assess the effects of school-based measures at different time points during the COVID-19 pandemic in the Netherlands. Our analyses suggest that the impact of measures reducing school-based contacts depends on the remaining opportunities to reduce non-school-based contacts. If opportunities to reduce the effective reproduction number (Re) with non-school-based measures are exhausted or undesired and Re is still close to 1, the additional benefit of school-based measures may be considerable, particularly among older school children. As two examples, we demonstrate that keeping schools closed after the summer holidays in 2020, in the absence of other measures, would not have prevented the second pandemic wave in autumn 2020 but closing schools in November 2020 could have reduced Re below 1, with unchanged non-school-based contacts.


Subject(s)
COVID-19/epidemiology , COVID-19/prevention & control , Pandemics , SARS-CoV-2 , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Basic Reproduction Number/prevention & control , Basic Reproduction Number/statistics & numerical data , Bayes Theorem , COVID-19/transmission , Child , Child, Preschool , Cross-Sectional Studies , Female , Holidays , Hospitalization , Humans , Infant , Infant, Newborn , Male , Middle Aged , Models, Biological , Models, Statistical , Netherlands/epidemiology , Pandemics/prevention & control , Schools , Seroepidemiologic Studies , Young Adult
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