SARS-CoV-2 Seroprevalence Study in Pimpri-Chinchwad, Maharashtra, India Coinciding with Falling Trend – Do the Results Suggest Imminent Herd Immunity?

2020 ◽  
Author(s):  
Amitav Banerjee ◽  
Bhargav Gaikwad ◽  
Atul Desale ◽  
Sudhir L. Jadhav ◽  
Jitendra Bhawalkar ◽  
...  
2012 ◽  
Vol 140 (11-12) ◽  
pp. 751-755
Author(s):  
Vladimir Petrovic ◽  
Zorica Seguljev ◽  
Jasminka Nedeljkovic ◽  
Mioljub Ristic

Introduction. The seroprevalence study was performed in Vojvodina during May and June 2010 in order to asses the effects of the 2009 pandemic influenza A(H1N1)v epidemic on herd immunity. It was a part of the Serbian Ministry of Health funded nationwide study. Objective. Prevalence of antibodies against 2009 pandemic influenza A(H1N1)v was determined in a 1% sample of the population monitored for influenza-like illness and acute respiratory infections in Vojvodina through sentinel surveillance system. Methods. The study sample involved a total of 1004 inhabitants of Vojvodina. The control group consisted of randomly selected and age-adjusted 1054 sera collected in the pre-pandemic period. Sera were tested by the reaction of hemagglutination inhibition using influenza A/California/7/2009 (H1N1) antigen in dilution from 1:8 to 1:256. Antibody titers ?1:32 and ?1:8 were considered protective and diagnostic, respectively. Results. The differences between control and study sera in all age groups were significant for both diagnostic ?1/8 and protective titres ?1/32 of hemagglutination inhibition antibodies (chi square test, p<0.001). The highest percentage of seropositive subjects was registered in the age group 15-19 years followed by children aged 5-14 years. Both diagnostic and protective titres were about twice higher in the vaccinated as compared to the non-vaccinated group. There were no statistically significant differences in seroprevalence between seven districts of Vojvodina. Conclusion. The 2009 pandemic influenza A(H1N1)v epidemic significantly influenced the herd immunity in our population regardless of low immunization coverage with highest immunity levels in adolescents aged 15-19 years and with similar herd immunity levels in all the regions in the province six months after the outbreak.


2020 ◽  
Author(s):  
Amitav Banerjee ◽  
Bhargav Gaikwad ◽  
Atul Desale ◽  
Sudhir Laxman Jadhav ◽  
Jitendra Bhawalkar ◽  
...  

2021 ◽  
Author(s):  
Wilfredo Rafael Matias ◽  
Isabel R Fulcher ◽  
Sara M Sauer ◽  
Cody P Nolan ◽  
Yodeline Guillaume ◽  
...  

Background: Seroprevalence studies are important tools to estimate the prevalence of prior or recent SARS-CoV-2 infections, identifying hotspots and high-risk groups and informing public health responses to the COVID-19 pandemic. We conducted a city-level seroprevalence study in Holyoke, Massachusetts, USA to estimate the seroprevalence of SARS-CoV-2 antibodies and risk factors for seropositivity. Methods: We invited inhabitants of 2,000 randomly sampled addresses between November 5 and December 31, 2020. Participants completed questionnaires measuring sociodemographic and health characteristics, and COVID-19 exposure history, and provided dried blood spots for measurement of SARS-CoV-2 IgG and IgM antibodies. We calculate total and subgroup seroprevalence estimates based on presence of IgG antibodies using a Bayesian procedure that incorporates uncertainty in antibody test sensitivity and specificity. We account for clustering by household and weighting based on demographic characteristics to ensure estimates represented the citys population. Findings: We enrolled 280 households including 472 individuals. 328 underwent antibody testing. The citywide seroprevalence estimate of SARS-CoV-2 IgG was 13.1% (95%CI 6.9-22.3) compared to 9.8% based on publicly reported case counts. Seroprevalence was 16.1% (95%CI 6.2-31.8) among individuals identifying as Hispanic compared to 9.4% (95%CI 4.6-16.4) among those identifying as non-Hispanic white. Seroprevalence was higher among Spanish speaking households (21.9%; 95% CI 8.3-43.9) compared to English speaking households (10.2%; 95% CI 5.2-18.0) and among individuals living in high vulnerability areas (14.4%; 95% CI 7.1-25.5) compared to low vulnerability areas (8.2%; 95% CI 3.1-16.9). Interpretation: The measured SARS-CoV-2 seroprevalence of IgG antibodies in Holyoke was only 13.1% during the second surge of SARS-CoV-2 in this region, far from accepted thresholds for herd immunity. Already vulnerable communities were at highest risk of prior infection. Implementation of local serosurveys in tandem with proactive public health interventions that address disparities in SARS-CoV-2 exposure are crucial to ensure at-risk communities have appropriate educational materials and access to vaccines, testing, and timely treatment.


2020 ◽  
Vol 99 (6) ◽  
pp. 15-31
Author(s):  
A.A. Korenkova ◽  
◽  
E.M. Mayorova ◽  
V.V. Bahmetjev ◽  
M.V. Tretyak ◽  
...  

The new coronavirus infection has posed a major public health challenge around the world, but new data on the disease raises more questions than answers. The lack of optimal therapy is a significant problem. The article examines the molecular mechanisms of SARS-CoV-2 infection and the pathogenesis of COVID-19, special attention is paid to features of pathological processes and immune responses in children. COVID-19 leads to a wide diversity of negative outcomes, many of which can persist for at least months. Many of the consequences have yet to be identified. SARS-CoV-2 may provoke autoimmune reactions. Reinfection, herd immunity, vaccines and other prevention measures are also discussed in this review.


2020 ◽  
Author(s):  
Onamika Rani Sarker ◽  
Sabyasachi Antor Chanda
Keyword(s):  

2020 ◽  
Vol 16 (1) ◽  
pp. 6-11
Author(s):  
Ashok Arasu ◽  
Pavithra Balakrishnan ◽  
Thirunavukkarasu Velusamy ◽  
Thiagarajan Ramesh

The 2019 novel coronavirus (2019-nCoV) infection is an emerging pandemic that poses a severe threat to global public health. This pandemic started from the Wuhan City of Hubei Province in China, and is speculated to have originated from bats and spread among humans with an unknown intermediate transmitter. The virus binds to angiotensin-converting enzyme 2 (ACE2), which is abundantly expressed on various human cells, including lung epithelial and intestinal cells, thereby entering into these cells and causing infection. It is transmitted to other humans through airborne droplets from infected patients. Presently there are no specific treatments or vaccines that are available to curtail the spread of this disease. There are few indirect reports that explain the potential importance of the mandated BCG vaccine as a protective factor against COVID-19. There is a speculation that a live attenuated vaccine (BCG vaccine) can be beneficial against COVID-19 to develop the initial immune response, and can also spread in the community, thereby boosting herd immunity to fight against COVID-19. This review summarizes the conclusions of various reports on the BCG vaccine, and is an attempt to establish BCG-vaccination mediated herd immunity as an effective instant intermediate approach in curbing COVID-19 spread in highly populous countries.


2020 ◽  
Author(s):  
Laura Lafon-Hughes

BACKGROUND It is common knowledge that vaccination has improved our life quality and expectancy since it succeeded in achieving almost eradication of several diseases including chickenpox (varicella), diphtheria, hepatitis A and B, measles, meningococcal, mumps, pneumococcal, polio, rotavirus, rubella, tetanus and whooping cough (pertussis) Vaccination success is based on vaccine induction of neutralizing antibodies that help fight the infection (e.g. by a virus), preventing the disease. Conversely, Antibody-dependent enhancement (ADE) of a viral infection occurs when anti-viral antibodies facilitate viral entry into host cells and enhance viral infection in these cells. ADE has been previously studied in Dengue and HIV viruses and explains why a second infection with Dengue can be lethal. As already reviewed in Part I and Part II, SARS-Cov-2 shares with HIV not only 4 sequences in the Spike protein but also the capacity to attack the immune system. OBJECTIVE As HIV presents ADE, we wondered whether this was also the case regarding SARS-CoV-2. METHODS A literature review was done through Google. RESULTS SARS-CoV-2 presents ADE. As SARS, which does not have the 4 HIV-like inserts, has the same property, ADE would not be driven by the HIV-like spike sequences. CONCLUSIONS ADE can explain the failure of herd immunity-based strategies and will also probably hamper anti-SARS-CoV-2 vaccine development. As reviewed in Part I, there fortunately are promising therapeutic strategies for COVID-19, which should be further developed. In the meantime, complementary countermeasures to protect mainly the youth from this infection are presented to be discussed in Part V Viewpoint.


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