Herd Immunity: Understanding COVID-19

Randolph, Haley E.; Barreiro, Luis B.

doi:10.1016/j.immuni.2020.04.012

Cited by 1,053 publications

(1,093 citation statements)

References 15 publications

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“…Early observations in hospitalized patients reported IgG+ rates as high as 80% 26,27 to even 100% in longitudinal studies 28 . These data seeded the hope of reaching a protective herd immunity 29 . However, wide nationwide studies are reporting low seroprevalence rates 11,16,30 , which are promoting pessimistic perspectives between experts regarding the achievement of such herd immunity 31 .…”

Section: Discussionmentioning

confidence: 84%

IgG seroprevalence against SARS-CoV-2 in a cohort of 449 non-hospitalized, high-risk exposure individuals.

Martínez¹,

García²,

Salas³

et al. 2020

Preprint

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COVID-19 pandemic caused by SARS-CoV-2 led the Spanish government to impose a national lockdown in an attempt to control the spread of the infection. Mobility restrictions but also the requirement of a medical prescription to gain access to serological testing for COVID-19 were included among the measures. Under this scenario, between April 15th to June 15th, 2020, we performed a seroprevalence observational study including 449 individuals that fulfill prescription requirements: manifesting COVID-19 compatible symptoms, being in contact with a COVID-19 confirmed case or belonging to essential occupations including healthcare workers, firefighters or public safety personnel such as police. Importantly, none of the participants was hospitalized. Altogether, we studied this specific, non-commonly addressed cohort for SARS-CoV-2 seroprevalence, uncovering intrinsic features of great demographic interest. The overall rate of IgG seropositivity was 33.69% (95% CI: 29.27 – 38.21). This seroprevalence was comparable between different occupations performed by the participants. However, contacts with confirmed cases associated positively with IgG+ results, with stronger correlation if being a household member. The number of symptoms also correlated positively with IgG+ prevalence. Ageusia/anosmia, pneumonia and cutaneous manifestations were the top-three symptoms that most strongly associated with IgG+ seroprevalence. However, while pneumonia and cutaneous manifestations were barely present in our cohort, fever, ageusia/anosmia and asthenia were the most frequently symptoms described within IgG+ subjects. Therefore, our data illustrate how specific cohorts display heterogeneous characteristics that should be taken into account when identifying population seroprevalence against SARS-CoV-2 and key defining symptoms for COVID-19.

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Section: Discussionmentioning

confidence: 84%

IgG seroprevalence against SARS-CoV-2 in a cohort of 449 non-hospitalized, high-risk exposure individuals.

Martínez¹,

García²,

Salas³

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…It is of great importance to study and understand the process prevalence and response to COVID-19 in Syria because Syria has faced 10 long years of war, which laterally destroyed its health system, and currently under sanctions, which made it even harder for the under-poverty-line population to survive during this pandemic. With the lack of real and effective governmental measurements and decreased public awareness, we may be going straight ahead towards herd immunity, assuming an R0 estimate of 3 for SARS-CoV-2, and the herd immunity threshold is estimated to be 67%-80% (24,25). Considering that 67% of our sample reported COVID-19 symptoms, we may be close to achieving herd immunity, but this cannot be con rmed without widespread screening PCR tests to con rm the disease.…”

Section: Discussionmentioning

confidence: 92%

The Prevalence of COVID-19 Symptoms in Syria: A Cross-Sectional Study

Alhaffar

Abbas

Nassar

2020

Preprint

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Introduction: The corona virus disease 2019 is a disease caused by the newly discovered human infecting SARS-Co V-2 virus. The COVID-19 virus is highly transmittable, by August 14, 2020, more than 20 million people were confirmed to have COVID-19 worldwide, with more than 750,000 death. Syria was declared to have one of most vulnerable health systems in the world, with poor surveillance systems, unstable conditions, no standardized method for reporting infections, lack of sufficient public awareness, and a continued deterioration of humanitarian and socio-economic conditions across Syria.Objectives: to investigate the prevalence of COVID-19 symptoms among the Syrian population.Methods: this is a cross sectional study in Damascus – Syria, data were collected during August, 2020 using an online questionnaire that contained 3 section (demographic variables, awareness of COVID-19, symptoms of COVID-19) and analyzed using SPSS v.22.Results: 5212 people were included in the study, 59% females and 41% males, 9.6% had chronic medical conditions. 63.4% reported experiencing COVID-19 symptoms during the past 6 months, symptoms lasted 6.9 days on average, the most prevalent symptoms were as anosmia and dysgeusia (42.2%), headache (67.1%), fatigue (70%). Symptoms were significantly more prevalent in the past 14 days (P=0.000).Conclusion: Within the limits of this study, high prevalence of covid-19 symptoms was noticed in the Syrian population. Significant correlation was made between the severity and duration of the symptoms. Measures to slow down spread of COVID-19 need to be taken immediately.

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“…As an example, estimating the SARS-CoV-2 propagation speed by R 0 (basic reproduction number) of 3, herd immunity will have the strength to decrease the incidence of new infections when the percentage of acquired immunity is approximately 67%. 41 At the moment, several serological surveys point to population immunity ranging from 1.2 to 14%, and even in countries where isolation has not been adopted, such as Sweden, this immunity is around 7.5%. Assuming that herd immunity occurs at that percentage of 67%, we have a long way to go, living with high population susceptibility.…”

Section: Final Considerationsmentioning

confidence: 99%