Background The E484K and L452R amino acid substitutions on the spike protein of SARS-CoV-2 are associated with reduced neutralization by antibodies from acquired immunity. This study examines the respective association of these mutations with infection in persons who had previously received a COVID-19 vaccine.Methods Genetic sequences from SARS-CoV-2 specimens collected from Maryland residents and reported to Maryland Department of Health were linked to vaccination history. The prevalence of infections in fully vaccinated persons -- defined as being at least two weeks past receiving the final scheduled dose of a COVID-19 vaccine series -- was compared between infections caused by viruses carrying E484K to those not carrying E484K, and between infections caused by viruses carrying L452R to those not carrying L452R, using logistic regression to adjust for confounding.Results Of 9,048 sequenced SARS-CoV-2 specimens examined, 265 (2.9%) were collected from fully vaccinated persons. In adjusted analysis, the E484K substitution was associated with an increase in the odds of the sequenced specimen being collected from a fully vaccinated person (OR 1.96, 95% CI, 1.36 to 2.83). The L452R mutation was not significantly associated with infections in vaccinated persons (OR 1.07, 95% CI, 0.69 to 1.68).Conclusion Though more than 97% of SARS-CoV-2 infections were in persons who were not fully vaccinated, the E484K mutation was associated with increased odds of SARS-CoV-2 infection in vaccinated persons. Linking vaccination and sequencing data can help identify and estimate the impact SARS-CoV-2 mutations may have on vaccine effectiveness.Summary In viruses sequenced for Maryland’s routine SARS-CoV-2 genomic surveillance, the spike protein amino acid substitution E484K was more prevalent in viruses that infected vaccinated people than in viruses that infected people who were not vaccinated.Competing Interest StatementThe authors have declared no competing interest.Funding StatementNo external funding to report.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Case investigation, data collection, and analysis were conducted for public health purposes. This project was reviewed by the Division of Scientific Education and Professional Development within the Center for Surveillance, Epidemiology, and Laboratory Services at the Centers for Disease Control and Prevention (CDC). The project was determined to meet the requirements of public health surveillance covered by the U.S. Department of Health and Human Services Policy for the Protection of Human Research Subjects as defined in 45 C.F.R. part 46.102(l)(2), 21 C.F.R. part 56; 42 U.S.C. Sec.241(d); 5 U.S.C. Sec.552a; 44 U.S.C. Sec.3501 et seq. In., and the decision was made that this project was nonresearch and did not require ethical review by the CDC Human Research Protection Office. Ethical approval was waived and informed consent was not required.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData are the property of the U.S. state of Maryland and are collected for public health surveillance purposes. They are not available to the ublic.

Among 9048 people infected with SARS-CoV-2 between January and May 2021 in Maryland, in regression-adjusted analysis, SARS-CoV-2 viruses carrying the spike protein mutation E484K were disproportionately prevalent among persons infected after full vaccination against COVID-19 compared with infected persons who were not fully vaccinated (aOR, 1.96; 95% CI: 1.36-2.83).

In late January 2021, a clinical laboratory notified the Maryland Department of Health (MDH) that the SARS-CoV-2 variant of concern B.1.351 had been identified in a specimen collected from a Maryland resident with COVID-19 (1). The SARS-CoV-2 B.1.351 lineage was first identified in South Africa (2) and might be neutralized less effectively by antibodies produced after vaccination or natural infection with other strains (3-6). To limit SARS-CoV-2 chains of transmission associated with this index patient, MDH used contact tracing to identify the source of infection and any linked infections among other persons. The investigation identified two linked clusters of SARS-CoV-2 infection that included 17 patients. Three additional specimens from these clusters were sequenced; all three had the B.1.351 variant and all sequences were closely related to the sequence from the index patient's specimen. Among the 17 patients identified, none reported recent international travel or contact with international travelers. Two patients, including the index patient, had received the first of a 2-dose COVID-19 vaccination series in the 2 weeks before their likely exposure; one additional patient had a confirmed SARS-CoV-2 infection 5 months before exposure. Two patients were hospitalized with COVID-19, and one died. These first identified linked clusters of B.1.351 infections in the United States with no apparent link to international travel highlight the importance of expanding the scope and volume of genetic surveillance programs to identify variants, completing contact investigations for SARS-CoV-2 infections, and using universal prevention strategies, including vaccination, masking, and physical distancing, to control the spread of variants of concern.

In April 2020, during the peak of the coronavirus disease 2019 (COVID-19) pandemic in Europe, a cluster of children with hyperinflammatory shock with features similar to Kawasaki disease and toxic shock syndrome was reported in England* (1). The patients' signs and symptoms were temporally associated with COVID-19 but presumed to have developed 2-4 weeks after acute COVID-19; all children had serologic evidence of infection with SARS-CoV-2, the virus that causes COVID-19 (1). The clinical signs and symptoms present in this first cluster included fever, rash, conjunctivitis, peripheral edema, gastrointestinal symptoms, shock, and elevated markers of inflammation and cardiac damage (1). On May 14, 2020, CDC published an online Health Advisory that summarized the manifestations of reported multisystem inflammatory syndrome in children (MIS-C), outlined a case definition,(†) and asked clinicians to report suspected U.S. cases to local and state health departments. As of July 29, a total of 570 U.S. MIS-C patients who met the case definition had been reported to CDC. A total of 203 (35.6%) of the patients had a clinical course consistent with previously published MIS-C reports, characterized predominantly by shock, cardiac dysfunction, abdominal pain, and markedly elevated inflammatory markers, and almost all had positive SARS-CoV-2 test results. The remaining 367 (64.4%) of MIS-C patients had manifestations that appeared to overlap with acute COVID-19 (2-4), had a less severe clinical course, or had features of Kawasaki disease.(§) Median duration of hospitalization was 6 days; 364 patients (63.9%) required care in an intensive care unit (ICU), and 10 patients (1.8%) died. As the COVID-19 pandemic continues to expand in many jurisdictions, clinicians should be aware of the signs and symptoms of MIS-C and report suspected cases to their state or local health departments; analysis of reported cases can enhance understanding of MIS-C and improve characterization of the illness for early detection and treatment.