Using sero-epidemiology to monitor disparities in vaccination and infection with SARS-CoV-2

Abstract

Disease outbreaks often highlight existing inequalities and injustices within society. The COVID 19 pandemic has underscored long-existing health inequalities, both within countries and between the Global North and South. These disparities have been observed throughout the pandemic, from disparities in the severity and impact of the initial waves of cases to disparities in who was most protected during the roll-out of vaccination. As the Delta variant surges in many countries, structural inequalities shape the trajectory of the pandemic and exacerbate existing health disparities. In the age of vaccination, the double burden of disparities in both exposure to infection and vaccination coverage intersect to determine the current and future patterns of infection, immunity, and mortality. It is important to consider the ways in which these disparities, with overlapping but distinct drivers, interact to determine population-level immunity and the burden of COVID 19 in different communities. Individuals or communities can experience different pathways to immunity, whether through infection, vaccination, or both. Using San Francisco as a case study, we show how a seroepidemiological approach can illuminate disparities in the pathway to immunity.

Pediatric humoral immune responses and infection risk after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and two-dose vaccination during SARS-CoV-2 omicron BA.5 and BN.1 variants predominance in South Korea

“…However, we could not identify any statistical difference in anti-N IgG distributions between the different age groups in our study (Figure 3B). Previous studies have revealed differences between vaccinationinduced and SARS-CoV-2-induced seroprevalence across varying demographics (13,32). However, this study could not identify any significant sex-and age-related disparities in anti-S and anti-N IgG possibly because of the considerable number of children who had been infected by SARS-CoV-2 and had undergone COVID-19 vaccination in South Korea.…”

“…Furthermore, hybrid immunity acquired from both natural SARS-CoV-2 infection and COVID-19 vaccination reportedly generates greater humoral immunogenicity than either vaccination or natural SARS-CoV-2 infection alone (11). Although SARS-CoV-2 seroprevalence studies, including those focusing on immune response and COVID-19 vaccine effectiveness, have been conducted in various locations across several countries (11)(12)(13), most findings have largely been based on the adult population, and children have rarely been included.…”

Estimating SARS-CoV-2 Seroprevalence in Canadian Blood Donors, April 2020 to March 2021: Improving Accuracy with Multiple Assays

“…The second profile (profile 2), with RBD and Spike antibodies more predictive of seropositivity, would be expected in vaccinated people or potentially in people with a prior infection where nucleocapsid antibodies have waned ( 7 , 17 ). Among people with known vaccination status, test positivity profiles for RBD and Spike antibodies were consistent with expectation, but it is important to note that the lack of nucleocapsid may not be precise for classifying vaccine status, and some vaccinated people may also have been previously infected ( 1 , 14 ).…”

“…During the SARS-CoV-2 pandemic, serological studies have provided a number of key insights into this newly emerged infection; they have affirmed that development of an antibody response correlates with clearance of viral shedding ( 11 ); they have helped delineate the fraction of infections that are identified as cases ( 12 ); have permitted estimation of infection fatality ratios and have facilitated identification of groups and regions with elevated infection risks and ongoing vulnerabilities to infection ( 13 – 16 ). However, seroprevalence studies rely on assays with imperfect sensitivity and specificity ( 16 ).…”

Wastewater as a back door to serology?

“…In particular, vaccine-mediated immunity hinges on prompt boosting with updated vaccines that reflect circulating variants 8 . Currently rates of boosting in countries such as the United States are low and highly biased between populations 33 . As predicting the local impact of the next SARS-CoV-2 infection wave requires an estimate of the durability of the immune response from earlier vaccination or natural infection, wastewater-based assessments could allow such data to be rapidly collected and thereby identify populations at risk.…”