Lockdown measures and relative changes in the age-specific incidence of SARS-CoV-2 in Spain

Salazar, D.I. Molina de; Gómez-Barroso, Diana; Pampaka, Despina; Jm, Gil Vernet; B, Peñalver; Fernández-Escobar, Carlos; Lipsitch, Marc; Larrauri, Amparo; Goldstein, Édward; Hernán, Miguel A.

doi:10.1101/2020.06.30.20143560

Cited by 6 publications

(3 citation statements)

References 10 publications

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“…However, during the later strengthened lockdown, older adolescents and younger adults had an increased relative incidence of SARS-CoV-2 infection. 22 Our results, together with these observations, highlight the fact that control measures during a pandemic have differential effectiveness in different age groups.…”

Section: Discussionsupporting

confidence: 60%

On the increasing incidence of SARS-CoV- 2 in older adolescents and younger adults during the epidemic in Mexico

et al. 2021

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Objective. To estimate temporary changes in the incidence of SARS-CoV-2-confirmed hospitalizations (by date of symptom onset) by age group during and after the national lockdown. Materials and methods. For each age group g, we computed the proportion E(g) of individuals in that age group among all cases aged 10-59y during the early lockdown period (April 20-May 3, 2020), and the corresponding proportion L(g) during the late lockdown (May 18-31, 2020) and post-lockdown (June 15-28, 2020) periods and computed the prevalence ratio: PR(g)=L(g)/E(g). Results. For the late lockdown and post-lockdown periods, the highest PR values were found in age groups 15-19y (late: PR=1.69, 95%CI 1.05,2.72; post-lockdown: PR=2.05, 1.30,3.24) and 20-24y (late: PR=1.43, 1.10,1.86; post-lockdown: PR=1.49, 1.15,1.93). These estimates were higher in individuals 15-24y compared to those ≥30y. Conclusions. Adolescents and younger adults had an increased relative incidence of SARS-CoV-2 during late lockdown and post-lockdown periods. The role of these age groups should be considered when implementing future pandemic response efforts.

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Section: Discussionsupporting

confidence: 60%

On the increasing incidence of SARS-CoV- 2 in older adolescents and younger adults during the epidemic in Mexico

et al. 2021

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“…It must be noted, though, that the effect of age structure in the infected population under lockdown is still under debate. While the subject has hardly been analyzed in Portugal, there are indications from neighboring Spain that the posterior phases of a lockdown led to an increased proportion of infected adolescents and young adults (12), which may be mirrored in Portugal during the phased easing of the confinement measures. It must be noted that the increase in active cases in Portugal seems to be in line with reports elsewhere after the end of lockdowns, including in Europe.…”

Section: Resultsmentioning

confidence: 99%

On the Progression of COVID-19 in Portugal: A Comparative Analysis of Active Cases Using Non-linear Regression

Milhinhos

Costa

2020

Front. Public Health

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Portugal is often portrayed as a relatively successful case in the control of COVID-19's March 2020 outbreak in Europe due to timely confinement measures, commonly referred to as the "lockdown". As in other European Union member states, by late April, Portugal was preparing the phased loosening of such measures scheduled for the beginning of May. Despite a modest reduction in infection rates by that time, there was insufficient data to reliably forecast imminent scenarios. Using the South Korea data as scaffold, which became a paradigmatic case of recovery following a high number of infected people, we fitted the Portuguese data to biphasic models using non-linear regression and compared the two countries. The models, which yielded a good fit, showed that recovery would be slow, with over 50% active cases months after the lockdown. These findings acted at the time as a warning, showing that a high number of infected individuals, together with an unknown number of asymptomatic carriers, could increase the risk of a slow recovery, if not of new outbreaks. A month later, the models showed more favorable outcomes. However, shortly after, as the effects of leaving the lockdown became evident, the number of infections began rising again, leaving Portugal in a situation of inward and outward travel restrictions and baffling even the most conservative forecasts for the clearing of the pandemic.

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“…In scenarios with social distancing we assumed that 80% of cases are symptomatic or can be ascertained [28]. In surveys during the lock-down in the first wave of SARS-CoV-2 in the The Netherlands, it was shown that the daily number of community contacts was reduced by 71% to around 3.7 per day [29] and after the partial lifting of the measures the number of contacts slowly increased again. Similar decreases in contact numbers during the lock-down in the United Kingdom were reported by [30].…”

Section: Social Distancingmentioning

confidence: 99%

Isolation and Contact Tracing Can Tip the Scale to Containment of COVID-19 in Populations With Social Distancing

2021

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SARS-CoV-2 has established itself in all parts of the world, and many countries have implemented social distancing as a measure to prevent overburdening of health care systems. Here we evaluate whether and under which conditions containment of SARS-CoV-2 is possible by isolation and contact tracing in settings with various levels of social distancing. To this end we use a branching process model in which every person generates novel infections according to a probability distribution that is affected by the incubation period distribution, distribution of the latent period, and infectivity. The model distinguishes between household and non-household contacts. Social distancing may affect the numbers of the two types of contacts differently, for example while work and school contacts are reduced, household contacts may remain unchanged. The model allows for an explicit calculation of the basic and effective reproduction numbers, and of exponential growth rates and doubling times. Our findings indicate that if the proportion of asymptomatic infections in the model is larger than 30%, contact tracing and isolation cannot achieve containment for a basic reproduction number (ℛ0) of 2.5. Achieving containment by social distancing requires a reduction of numbers of non-household contacts by around 90%. If containment is not possible, at least a reduction of epidemic growth rate and an increase in doubling time may be possible. We show for various parameter combinations how growth rates can be reduced and doubling times increased by contact tracing. Depending on the realized level of contact reduction, tracing and isolation of only household contacts, or of household and non-household contacts are necessary to reduce the effective reproduction number to below 1. In a situation with social distancing, contact tracing can act synergistically to tip the scale toward containment. These measures can therefore be a tool for controlling COVID-19 epidemics as part of an exit strategy from lock-down measures or for preventing secondary waves of COVID-19.

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Lockdown measures and relative changes in the age-specific incidence of SARS-CoV-2 in Spain

Cited by 6 publications

References 10 publications

On the increasing incidence of SARS-CoV- 2 in older adolescents and younger adults during the epidemic in Mexico

On the increasing incidence of SARS-CoV- 2 in older adolescents and younger adults during the epidemic in Mexico

On the Progression of COVID-19 in Portugal: A Comparative Analysis of Active Cases Using Non-linear Regression

Isolation and Contact Tracing Can Tip the Scale to Containment of COVID-19 in Populations With Social Distancing

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