SARS-CoV-2: big seroprevalence data from Pakistan—is herd immunity at hand?

Abstract

Purpose Seroprevalence surveys from different countries have reported SARS CoV-2 antibodies below 20% even in the most adversely affected areas and herd immunity cannot be predicted till more than half of the population gets the disease. The purpose of this survey was to estimate the magnitude of community-based spread of the infection, associated immunity, and the future prospects and proximity to a 'herd community'. Methods The study was undertaken as a cluster randomized, cross-sectional countrywide survey. This largest communitybased seroprevalence data of SARS-CoV-2 were collected between 15th and 31st July, 2020 from seven randomly selected cities belonging to the three most populous provinces of Pakistan. The FDA approved kit of ROCHE was used for detection of SARS-CoV-2 antibodies. Results Serum samples of 15,390 participants were tested for SARS CoV-2 antibodies with an overall seroprevalence of 42.4%. The seroprevalence ranged from 31.1% to 48.1% in different cities with the highest in Punjab province (44.5%). In univariable analysis, the odds of seropositivity was higher in men compared to women (OR: 1.10, 95% CI: 1.01-1.19, P < 0.05). In multivariable analysis, the risk of being seropositive was lower (OR 0.72, 95% CI: 0.60-0.87, P < 0.01) in younger group (≤ 20 years) than in those aged above 60 years. ConclusionThe study concluded that despite a reasonable seroprevalence, the country is yet to reach the base minimum of estimations for herd immunity. The durability of immunity though debated at the moment, has shown an evidenced informed shift towards longer side.

High Prevalence of Undocumented SARS-CoV-2 Infections in the Pediatric Population of the Tyrolean District of Schwaz

“…When looking at the proportion of pediatric seroprevalence in a given population, previous studies found conflicting evidence regarding children’s share. Several early works have reported pediatric seroprevalence to be the lowest among age groups [ 40 , 41 , 42 , 43 ]. Likewise, in another Tyrolean hotspot, Ischgl, Knabl et al found a significantly lower seroprevalence in the pediatric population of 27.1% as opposed to 45% in the adult population in April 2020 [ 44 ].…”

How do we…form and coordinate a national serosurvey of SARS‐CoV‐2 within the blood collection industry?

“…Shortly after the emergence of SARS‐CoV‐2, a number of large‐scale, population‐based serological studies with random sampling were undertaken to achieve an accurate estimate of seroprevalence. 16 , 17 , 18 , 19 , 20 , 21 , 22 Although studies employing random sampling of households are representative, they are also resource intensive and therefore have often been limited to narrow geographic areas and/or single points in time. CDC pursued a more practical approach based on the use of residual blood specimens from commercial laboratories 23 and blood donors, 3 the latter of which was the design of this study.…”

“…The first objective, determining the proportion of the population that has been infected over time, was the most immediate need when the effort began. Shortly after the emergence of SARS‐CoV‐2, a number of large‐scale, population‐based serological studies with random sampling were undertaken to achieve an accurate estimate of seroprevalence 16–22 . Although studies employing random sampling of households are representative, they are also resource intensive and therefore have often been limited to narrow geographic areas and/or single points in time.…”

Seroprevalence of SARS-CoV2 Antibodies among Patients and Healthy Individuals of Lahore

“…7,8 Therefore, a seroepidemiological survey is essential to timely estimate COVID-19 virus infection rates, as the good progression of the epidemic in the community will eventually help the policymakers institute effective health measures. 9,10 Given Pakistan's limited testing capability focusing solely on symptom-based PCR tests, seroprevalence studies are required to identify the real scope of the illness and how far we have progressed in attaining herd immunity. Therefore, we undertook this study to estimate the seroprevalence of SARS-CoV2 antibodies in patients and healthy individuals presenting to a tertiary care hospital in Lahore.…”