High Prevalence of SARS-CoV-2 Omicron Infection Despite High Seroprevalence, Sweden, 2022

Abstract

We performed 2 surveys during 2022 to estimate point prevalences of SARS-CoV-2 infection compared with overall seroprevalence in Sweden. Point prevalence was 1.4% in March and 1.5% in September. Estimated seroprevalence was >80%, including among unvaccinated children. Continued SARS-CoV-2 surveillance is necessary for detecting emerging, possibly more pathogenic variants.

Estimating SARS‐CoV‐2 infections and associated changes in COVID‐19 severity and fatality

“…Despite these heterogeneities, estimates of the Italian SARS‐CoV‐2 seroprevalence obtained through the proposed modeling approach are in line with those estimated for high‐income European countries. 35 , 56 We thus expect the general trends and conclusions of this study may apply also to other high‐income European countries, as well as to other countries that have adopted a similar mitigation approach throughout the pandemic. Finally, our results suggest that our approach may represent a valid alternative to assess SARS‐CoV‐2 infection rates based on routinely collected surveillance data, when serological data are not available.…”

UB-612 pan-SARS-CoV-2 T cell immunity-promoting vaccine protects against COVID-19 moderate-severe disease

“… 19 , 20 Additionally, with the emergence of increasingly contagious Omicron variants, there is a potential for them to overcome immunity conferred by vaccination, prior infection, or hybrid immunity, posing a risk even to highly vaccinated individuals. 21 Furthermore, any reinfection, regardless of severity, would heighten the risks of mortality, hospitalization, and other health complications, including burden of long COVID. 22 , 23 This means that there is no risk-free scenario for COVID-19 reinfection, especially for the elderly, immunocompromised individuals, and those with underlying health conditions.…”

Humoral Responses Elicited after a Fifth Dose of SARS-CoV-2 mRNA Bivalent Vaccine

“…Also, due to the high transmissibility of the Omicron subvariants and low humoral responses, the vaccine provides weak protection against infection [ 23 ]. Thus, many studies have shown that breakthrough infections (BTIs, i.e., infection of a vaccinated individual) frequently occur and a significant part of the population has been infected at least once [ 24 , 25 , 26 ]. However, this increase in the number of BTIs is not accompanied by a significant increase in hospitalizations or deaths, indicating that immune memory elicited by previous infections and/or vaccination are still effective in preventing severe forms of COVID-19 despite weak neutralizing responses [ 27 , 28 , 29 ].…”

“…Days between the fifth dose and W3-Va5 b 21(21)(22)(23)(24)(25) 26(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37) a Values displayed are numbers. b Values displayed are medians, with interquartile ranges in parentheses.…”