scholarly journals Increased transmissibility of SARS-CoV-2 lineage B.1.1.7 by age and viral load

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Frederik Plesner Lyngse ◽  
Kåre Mølbak ◽  
Robert Leo Skov ◽  
Lasse Engbo Christiansen ◽  
Laust Hvas Mortensen ◽  
...  
Keyword(s):  
Risk Factors ◽  
Viral Load ◽  
Administrative Data ◽  
Attack Rate ◽  
Neutralizing Antibodies ◽  
Primary Case ◽  
Alpha Variant ◽  
Full Population

AbstractNew lineages of SARS-CoV-2 are of potential concern due to higher transmissibility, risk of severe outcomes, and/or escape from neutralizing antibodies. Lineage B.1.1.7 (the Alpha variant) became dominant in early 2021, but the association between transmissibility and risk factors, such as age of primary case and viral load remains poorly understood. Here, we used comprehensive administrative data from Denmark, comprising the full population (January 11 to February 7, 2021), to estimate household transmissibility. This study included 5,241 households with primary cases; 808 were infected with lineage B.1.1.7 and 4,433 with other lineages. Here, we report an attack rate of 38% in households with a primary case infected with B.1.1.7 and 27% in households with other lineages. Primary cases infected with B.1.1.7 had an increased transmissibility of 1.5–1.7 times that of primary cases infected with other lineages. The increased transmissibility of B.1.1.7 was multiplicative across age and viral load.

scholarly journals Household transmission of SARS-CoV-2 in Norway; a prospective, longitudinal study showing increased transmissibility of the Alpha variant (B.1.1.7) compared with other variants

2021 ◽  
Author(s):  
Cathinka Halle Julin ◽  
Anna Hayman Robertson ◽  
Olav Hungnes ◽  
Gro Tunheim ◽  
Terese Bekkevold ◽  
...  
Keyword(s):  
Risk Factors ◽  
Longitudinal Study ◽  
Close Contact ◽  
Questionnaire Data ◽  
Primary Case ◽  
Prospective Longitudinal Study ◽  
Household Contacts ◽  
Household Transmission ◽  
Alpha Variant ◽  
Prospective Longitudinal

ABSTRACT Background We studied the secondary attack rate (SAR), risk factors, and precautionary practices of household transmission in a prospective longitudinal study. Moreover, we compared household transmission between the Alpha (B.1.1.7) variant and non-variants of concern (non-VOCs). Methods We recruited households of confirmed COVID-19 cases from May 2020 to May 2021. Households received 8 home visits over 6 weeks. Biological samples and questionnaire data were collected. Results We recruited 70 confirmed COVID-19 cases and 146 household contacts. Transmission occurred in 60% of the households; the overall SAR for household contacts was 49.6%. The SAR was significantly higher for the Alpha variant (77.8%) compared with non-VOC variants (42.5%) and was associated with a higher viral load. SAR was higher in household contacts aged ≥40 years (64%) than in younger contacts (40-47%), and for contacts of cases with loss of taste/smell. Close contact prior to confirmation of infection tended to give a higher SAR. A significantly lower SAR was found for sleeping separately from the primary case after confirmation of infection. Conclusion We found substantial household transmission, particularly for the Alpha variant. Precautionary practices seem to reduce SAR; however, prevention of transmission within households may become difficult with more transmissible variants.

scholarly journals Increased Transmissibility of SARS-CoV-2 Lineage B.1.1.7 by Age and Viral Load: Evidence from Danish Households

2021 ◽  
Author(s):  
Frederik Plesner Lyngse ◽  
Kåre Mølbak ◽  
Robert Leo Skov ◽  
Lasse Engbo Christiansen ◽  
Laust Hvas Mortensen ◽  
...  
Keyword(s):  
Viral Load ◽  
Neutralizing Antibodies ◽  
Decision Makers ◽  
Rt Pcr ◽  
Primary Case ◽  
Important Public Health ◽  
Household Transmission ◽  
Multiplicative Effect ◽  
New Knowledge ◽  
Pharmaceutical Interventions

Aim The aim of this study was to estimate the household transmissibility of SARSCoV-2 for lineage B.1.1.7 compared with other lineages, by age and viral load. Furthermore, we wanted to estimate whether there is a multiplicative or additive effect of the increased transmissibility of B.1.1.7 compared with other lineages. Background New lineages of SARS-CoV-2 are of potential concern due to higher transmissibility, risk of severe outcomes, and/or escape from neutralizing antibodies. Lineage B.1.1.7 has been estimated to be more transmissible than other previously known lineages, but the association between transmissibility and risk factors, such as age of primary case and viral load is still unknown. Methods We used comprehensive administrative data from Denmark, comprising the full population, all SARS-CoV-2 RT-PCR tests, and all WGS lineage data (January 11 to February 7, 2021), to estimate household transmissibility stratified by lineage B.1.1.7 and other lineages. Results We included 5,241 households with primary cases; 808 were infected with SARS-CoV-2 lineage B.1.1.7 and 4,433 were infected with other lineages. The attack rate was 38% in households with a primary case infected with B.1.1.7 and 27% in households with a primary case infected with other lineages. Primary cases infected with B.1.1.7 had an increased transmissibility of 1.5-1.7 times that of primary cases infected with other lineages. The increased transmissibility of B.1.1.7 was multiplicative across age and viral load. Conclusions The results found in this study add new knowledge that can be used to mitigate the further spread of SARS-CoV-2 lineage B.1.1.7, which is becoming increasingly widespread in numerous countries. Our results clarify that the transmissibility of B.1.1.7 should be included as a multiplicative effect in mathematical models used as a tool for decision makers. The results may have important public health implications, as household transmission may serve as a bridge between otherwise separate transmission domains, such as schools and physical workplaces, despite implemented non-pharmaceutical interventions.

scholarly journals Household Transmission of SARS-CoV-2: A Prospective Longitudinal Study Showing Higher Viral Load and Increased Transmissibility of the Alpha Variant Compared to Previous Strains

2021 ◽  
Vol 9 (11) ◽  
pp. 2371
Author(s):  
Cathinka Halle Julin ◽  
Anna Hayman Robertson ◽  
Olav Hungnes ◽  
Gro Tunheim ◽  
Terese Bekkevold ◽  
...  
Keyword(s):  
Viral Load ◽  
Longitudinal Study ◽  
Digital Pcr ◽  
Primary Case ◽  
Prospective Longitudinal Study ◽  
Viral Loads ◽  
Household Contacts ◽  
Household Transmission ◽  
Alpha Variant ◽  
Prospective Longitudinal

We studied the secondary attack rate (SAR), risk factors, and precautionary practices of household transmission in a prospective, longitudinal study. We further compared transmission between the Alpha (B.1.1.7) variant and non-Variant of Concern (non-VOC) viruses. From May 2020 throughout April 2021, we recruited 70 confirmed COVID-19 cases with 146 household contacts. Participants donated biological samples eight times over 6 weeks and answered questionnaires. SARS-CoV-2 infection was detected by real-time RT-PCR. Whole genome sequencing and droplet digital PCR were used to establish virus variant and viral load. SARS-CoV-2 transmission occurred in 60% of the households, and the overall SAR for household contacts was 50%. The SAR was significantly higher for the Alpha variant (78%) compared with non-VOC viruses (43%) and was associated with a higher viral load. SAR was higher in household contacts aged ≥40 years (69%) than in younger contacts (40–47%), and for contacts of primary cases with loss of taste/smell. Children had lower viral loads and were more often asymptomatic than adults. Sleeping separately from the primary case reduced the risk of transmission. In conclusion, we found substantial household transmission, particularly for the Alpha variant. Precautionary practices seem to reduce SAR, but preventing household transmission may become difficult with more contagious variants, depending on vaccine use and effectiveness.

scholarly journals Latino Household Transmission of SARS-CoV-2

2021 ◽  
Author(s):  
Diego A Martinez ◽  
Eili Y Klein ◽  
Cassandra Parent ◽  
Diana Prieto ◽  
Benjamin F Bigelow ◽  
...  
Keyword(s):  
Risk Factors ◽  
Attack Rate ◽  
Temporal Changes ◽  
Household Transmission ◽  
Alpha Variant

Abstract We assessed temporal changes in the household secondary attack rate of SARS-CoV-2 and identified risk factors for transmission in vulnerable Latino households of Baltimore, Maryland. The household SAR was 45.8%, and it appeared to increase as the alpha variant spread, highlighting the magnified risk of spread in unvaccinated populations.

scholarly journals Adenovirus viremia may predict adenovirus pneumonia severity in immunocompetent children

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ruimu Zhang ◽  
Hongmei Wang ◽  
Shufeng Tian ◽  
Jikui Deng
Keyword(s):  
Risk Factors ◽  
Viral Load ◽  
Disease Severity ◽  
Mycoplasma Pneumoniae ◽  
Quantitative Polymerase Chain Reaction ◽  
Univariate Analysis ◽  
Clinical Manifestations ◽  
Pneumonia Severity ◽  
Adenovirus Pneumonia ◽  
Blood Viral Load

Abstract Background Previous studies have demonstrated an association between adenovirus viremia and disease severity in immunocompromised children. However, few studies have focused on this association in immunocompetent children. This study explored the association between adenovirus viremia and adenovirus pneumonia severity in immunocompetent children. Methods We performed a retrospective, observational study of immunocompetent children with adenovirus pneumonia admitted to Shenzhen Children’s Hospital in Shenzhen, China. Pneumonia was classified as severe or mild based on the Chinese guideline for the classification of pneumonia severity. Serum samples from all the children included in the study were tested for adenovirus DNA with a quantitative polymerase chain reaction. Clinical manifestations, laboratory examinations, and disease severity were compared between children with severe and mild pneumonia. Results A total of 111 immunocompetent children with adenovirus pneumonia (60 severe, 51 mild) were included. The median age was 40 months, and 64 patients were male. Five patients were admitted to the intensive care unit, and two underwent endotracheal intubation. All patients were discharged after recovery or improvement. Univariate analysis and binary logistic regression analysis showed that leukocytosis (OR = 1.1; 95% CI: 1.0 to 1.2; P = 0.033), co-infection with Mycoplasma pneumoniae (OR = 5.0; 95% CI: 2.1 to 12.3; P <  0.001), and high blood viral load (OR = 1.5; 95% CI: 1.2 to 2.0; P = 0.001) may be risk factors for severe adenovirus pneumonia. Conclusions Leukocytosis, co-infection with Mycoplasma pneumoniae, and high blood viral load may be risk factors for severe adenovirus pneumonia in immunocompetent children. Blood viral load may predict pneumonia severity.

scholarly journals Risk Factors for Kaposi’s Sarcoma–Associated Herpesvirus DNA in Blood and in Saliva in Rural Uganda

2019 ◽  
Vol 71 (4) ◽  
pp. 1055-1062 ◽  
Author(s):  
Angela Nalwoga ◽  
Marjorie Nakibuule ◽  
Vickie Marshall ◽  
Wendell Miley ◽  
Nazzarena Labo ◽  
...  
Keyword(s):  
Risk Factors ◽  
Viral Load ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Young Males ◽  
Viral Shedding ◽  
Antibody Titres ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Ugandan Population

Abstract Background Detectable Kaposi’s sarcoma–associated herpesvirus (KSHV) DNA in blood and increased antibody titres may indicate KSHV reactivation, while the transmission of KSHV occurs via viral shedding in saliva. Methods We investigated the risk factors for KSHV DNA detection by real-time polymerase chain reaction in blood and by viral shedding in saliva, in 878 people aged 3 to 89 years of both sexes in a rural Ugandan population cohort. Helminths were detected using microscopy and the presence of malaria parasitaemia was identified using rapid diagnostic tests. Regression modelling was used for a statistical analysis. Results The KSHV viral load in blood did not correlate with the viral load in saliva, suggesting separate immunological controls within each compartment. The proportions of individuals with a detectable virus in blood were 23% among children aged 3–5 years and 22% among those 6–12 years, thereafter reducing with increasing age. The proportions of individuals with a detectable virus in saliva increased from 30% in children aged 3–5 years to 45% in those aged 6–12 years, and decreased subsequently with increasing age. Overall, 29% of males shed in saliva, compared to 19% of females (P = .008). Conclusions Together, these data suggest that young males may be responsible for much of the onward transmission of KSHV. Individuals with a current malaria infection had higher levels of viral DNA in their blood (P = .031), compared to uninfected individuals. This suggests that malaria may lead to KSHV reactivation, thereby increasing the transmission and pathogenicity of the virus.

scholarly journals Nucleocapsid vaccine elicits spike-independent SARS-CoV-2 protective immunity

2021 ◽  
Author(s):  
William E. Matchett ◽  
Vineet Joag ◽  
J. Michael Stolley ◽  
Frances K. Shepherd ◽  
Clare F. Quarnstrom ◽  
...  
Keyword(s):  
Weight Loss ◽  
Viral Load ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Protein A ◽  
Receptor Binding Domain ◽  
Immune Effector ◽  
N Protein ◽  
Viral Antigens ◽  
Successful Vaccine

AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Neutralizing antibodies target the receptor binding domain of the spike (S) protein, a focus of successful vaccine efforts. Concerns have arisen that S-specific vaccine immunity may fail to neutralize emerging variants. We show that vaccination with HAd5 expressing the nucleocapsid (N) protein can establish protective immunity, defined by reduced weight loss and viral load, in both Syrian hamsters and k18-hACE2 mice. Challenge of vaccinated mice was associated with rapid N-specific T cell recall responses in the respiratory mucosa. This study supports the rationale for including additional viral antigens, even if they are not a target of neutralizing antibodies, to broaden epitope coverage and immune effector mechanisms.

scholarly journals Methodology for sampling women at high maternal risk in administrative data

2019 ◽  
Author(s):  
Jennifer Vanderlaan ◽  
Anne Dunlop ◽  
Roger Rochat ◽  
Bryan Williams ◽  
Susan E. Shapiro
Keyword(s):  
Risk Factors ◽  
Administrative Data ◽  
Conventional Method ◽  
Maternal Morbidity ◽  
Sample Selection ◽  
Population Level ◽  
Risk Identification ◽  
Net Benefit ◽  
Maternal Risk ◽  
Risk Scoring

Abstract Background In population level studies, the conventional practice of categorizing women into low and high maternal risk samples relies upon ascertaining the presence of various comorbid conditions in administrative data. Two problems with the conventional method include variability in the recommended comorbidities to consider and inability to distinguish between maternal and fetal risks. High maternal risk sample selection may be improved by using the Obstetric Comorbidity Index (OCI), a system of risk scoring based on weighting comorbidities associated with maternal end organ damage. The purpose of this study was to compare the net benefit of using OCI risk scoring vs the conventional risk identification method to identify a sample of women at high maternal risk in administrative data. Methods This was a net benefit analysis using linked delivery hospitalization discharge and vital records data for women experiencing singleton births in Georgia from 2008-2012. We compared the value identifying a sample of women at high maternal risk using the OCI score to the conventional method of dichotomous identification of any comorbidities. Value was measured by the ability to select a sample of women designated as high maternal risk who experienced severe maternal morbidity or mortality. Results The high maternal risk sample created with the OCI had a small but positive net benefit (+ 0.6), while the conventionally derived sample had a negative net benefit indicating the sample selection performed worse than identifying no woman as high maternal risk. Conclusions The OCI can be used to select women at high maternal risk in administrative data. The OCI provides a consistent method of identification for women at risk of maternal morbidity and mortality and avoids confounding all obstetric risk factors with specific maternal risk factors. Using the OCI may help reduce misclassification as high maternal risk and improve the consistency in identifying women at high maternal risk in administrative data.

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