Impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccination and Pediatric Age on Delta Variant Household Transmission

Ng, Oon Tek; Koh, Vanessa; Chiew, Calvin J; Marimuthu, Kalisvar; Thevasagayam, Natascha May; Mak, Tze Minn; Chua, Joon Kiat; Ong, Shannen Si Hui; Lim, Yong Kai; Ferdous, Zannatul; Johari, Alifa Khairunnisa bte; Cui, Lin; Lin, Raymond Tzer Pin; Tan, Kelvin Bryan; Cook, Alex R.; Leo, Yee‐Sin; Lee, Vernon J M

doi:10.1093/cid/ciac219

Cited by 16 publications

(18 citation statements)

References 19 publications

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“…During these waves there has been speculation that children have become more susceptible to SARS-CoV-2 infection and more infectious once they contract the virus. For example, during the Delta wave in Singapore children (aged 0-11 years) were significantly more likely to transmit and acquire SARS-CoV-2 in a household compared to young adults (18-29 years) [5]. Similarly, during the Omicron wave in the USA the secondary attack rates (SAR) were consistently high across household contact and index age groups, including those aged 0-4 years old [6].…”

Section: Introductionmentioning

confidence: 99%

The Role of Children in SARS-CoV-2 Variant of Concerns Transmission within Households: A Meta-analysis

Zhu

Xia

Pickering

et al. 2022

Preprint

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Meta-analysis and single site studies have established that children are less infectious within a household when positive for ancestral SARS-CoV-2. In addition, children appear less susceptible to infection when exposed to ancestral SARS-CoV-2 within a household. The emergence of SARS-CoV-2 variants of concern (VOC) has been associated with an increased number of pediatric infections worldwide. However, the role of children in the household transmission of VOCs, relative to the ancestral virus, remains unclear. Here, we perform a meta-analysis of the role of children in the household transmission of both ancestral SARS-CoV-2 and SARS-CoV-2 VOCs. Unlike the ancestral virus, children infected with VOCs spread SARS-CoV-2 to an equivalent number of household contacts as infected adults. Similarly, unlike the ancestral virus, children within a household were equally as likely as adults to acquire SARS-CoV-2 from an infected family member. Interestingly, this same observation was noted when unvaccinated children exposed to VOCs were compared to unvaccinated adults exposed to VOCs. Together, these data suggest that the emergence of VOCs were associated with a fundamental shift in the epidemiology of SARS-CoV-2. This is unlikely to solely be the result of age-dependent differences in vaccination during the VOCs period and instead may reflect virus evolution over the course of the pandemic.

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Section: Introductionmentioning

confidence: 99%

The Role of Children in SARS-CoV-2 Variant of Concerns Transmission within Households: A Meta-analysis

Zhu

Xia

Pickering

et al. 2022

Preprint

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Section: Resultsmentioning

confidence: 99%

“…Some studies (4/15) summarised the vaccination status of the entire study sample, which ranged from an undefined proportion of partially vaccinated individuals to 70% fully vaccinated, without analysing it at the individual level for adults and children and adolescents. 17,[56][57][58] Six studies evaluated data from alpha variant outbreaks in daycare centres and compared the risk of infection between children and adults. 14,18,[50][51][52][53] They generally showed a lower attack rate for infection with the alpha variant ranging from 0% to 27% for young children (mostly ≤6 years old) than for adults (0%-71%).…”

Section: Review Question 1: Symptoms and Severity Of Disease Among Ch...mentioning

confidence: 99%

“…16,19 Data on the risk of infection during the delta predominant time period analysed in four studies comparing children and adolescents to adults were inconclusive. [55][56][57][58] Two of these four studies, one cohort study from Singapore and one from the UK found the risk of infection to be higher for younger children ≤11years old/school-aged children 5-18 years old than for adults who were either completely or partially vaccinated. 57,58 .…”

Section: Review Question 1: Symptoms and Severity Of Disease Among Ch...mentioning

confidence: 99%

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The role of SARS-CoV-2 variants of concern in children and adolescents with COVID-19: a systematic review

Wiedenmann

Ipekci

Chaveron

et al. 2023

Preprint

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Background: Infections by SARS-CoV-2 variants of concern (VOCs) might affect children and adolescents differently than earlier viral lineages. We aimed to address five questions about SARS-CoV-2 VOC infections in children and adolescents: i) symptoms and severity, ii) risk factors for severe disease, iii) the risk of becoming infected, iv) the risk of transmission and v) long-term consequences following a VOC infection. Methods: We carried out a systematic review. We searched the COVID-19 Open Access Project database up to 1 March 2022 and PubMed up to 9 May 2022 for observational epidemiological studies about alpha, beta, gamma, delta and omicron VOCs among 0 to 18 year olds. We synthesised data for each question descriptively and assessed the risks of bias at the outcome level. Results: We included 53 articles, of which 47% were from high-income countries and none were from low-income countries, according to World Bank categories. Most children with any VOC infection presented with mild disease, with more severe disease being described with the delta or the gamma VOC. Diabetes and obesity were reported as risk factors for severe disease during the whole pandemic period. The risk of becoming infected with a SARS-CoV-2 VOC seemed to increase with age, while in daycare settings the risk of onward transmission of VOCs was higher for younger than older children or at least partially vaccinated adults. Long-term symptoms or signs following an infection with a VOC were described in <5% of children and adolescents. Conclusion: Overall patterns of SARS-CoV-2 VOC infections in children and adolescents are similar to those of earlier lineages. Comparisons between different pandemic periods, countries and age groups should be improved with complete reporting of relevant contextual factors, including VOCs, vaccination status of study participants and the risk of exposure of the population to SARS-CoV-2.

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“…Oon Tek Ng et al ( 20 ) reported that among the Delta variant-exposed household contacts, the male index cases (adjusted odds ratio (aOR), 0.86; 95% CI, 0.49–1.49) had no significant association with the reduced risk of SARS-CoV-2 acquisition. Meanwhile, another study ( 21 ) by Oon Tek Ng et al showed that male index cases had a significant association with an increased risk of SARS-CoV-2 acquisition (aOR, 1.23; 95% CI, 1.04–1.46) among the Delta variant-exposed household contacts. More studies are needed regarding the association between the gender of the index cases and household SAR.…”

Section: Discussionmentioning

confidence: 99%

Dynamic characteristics of a COVID-19 outbreak in Nanjing, Jiangsu province, China

Wang

Ding

et al. 2022

Front. Public Health

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ObjectivesSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage B.1.617.2 (also named the Delta variant) was declared as a variant of concern by the World Health Organization (WHO). This study aimed to describe the outbreak that occurred in Nanjing city triggered by the Delta variant through the epidemiological parameters and to understand the evolving epidemiology of the Delta variant.MethodsWe collected the data of all COVID-19 cases during the outbreak from 20 July 2021 to 24 August 2021 and estimated the distribution of serial interval, basic and time-dependent reproduction numbers (R0 and Rt), and household secondary attack rate (SAR). We also analyzed the cycle threshold (Ct) values of infections.ResultsA total of 235 cases have been confirmed. The mean value of serial interval was estimated to be 4.79 days with the Weibull distribution. The R0 was 3.73 [95% confidence interval (CI), 2.66–5.15] as estimated by the exponential growth (EG) method. The Rt decreased from 4.36 on 20 July 2021 to below 1 on 1 August 2021 as estimated by the Bayesian approach. We estimated the household SAR as 27.35% (95% CI, 22.04–33.39%), and the median Ct value of open reading frame 1ab (ORF1ab) genes and nucleocapsid protein (N) genes as 25.25 [interquartile range (IQR), 20.53–29.50] and 23.85 (IQR, 18.70–28.70), respectively.ConclusionsThe Delta variant is more aggressive and transmissible than the original virus types, so continuous non-pharmaceutical interventions are still needed.

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Impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccination and Pediatric Age on Delta Variant Household Transmission

Cited by 16 publications

References 19 publications

The Role of Children in SARS-CoV-2 Variant of Concerns Transmission within Households: A Meta-analysis

The Role of Children in SARS-CoV-2 Variant of Concerns Transmission within Households: A Meta-analysis

The role of SARS-CoV-2 variants of concern in children and adolescents with COVID-19: a systematic review

Dynamic characteristics of a COVID-19 outbreak in Nanjing, Jiangsu province, China

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