Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study
BackgroundSARS-CoV-2 infection does not confer long immunity. However, studies suggest that prior infection is associated with lower risk of reinfection and milder outcomes of recurrent infections. The aims of this retrospective observational case-control study were to describe the clinical and mole...
| Main Authors: | , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2022-10-01
|
| Series: | Frontiers in Medicine |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmed.2022.962653/full |
| _version_ | 1811196223453921280 |
|---|---|
| author | Alen Suljič Maja Sočan Maja Mrzel Maja M. Lunar Miša Korva Alenka Štorman Katarina Prosenc Sandra Janežič Tjaša Žohar-Čretnik Tina Zupanič Mario Poljak Tatjana Avšič-Županc |
| author_facet | Alen Suljič Maja Sočan Maja Mrzel Maja M. Lunar Miša Korva Alenka Štorman Katarina Prosenc Sandra Janežič Tjaša Žohar-Čretnik Tina Zupanič Mario Poljak Tatjana Avšič-Županc |
| author_sort | Alen Suljič |
| collection | DOAJ |
| description | BackgroundSARS-CoV-2 infection does not confer long immunity. However, studies suggest that prior infection is associated with lower risk of reinfection and milder outcomes of recurrent infections. The aims of this retrospective observational case-control study were to describe the clinical and molecular characteristics of genetically confirmed Delta reinfection cases and to assess the potential protective role of preceding infection on the severity of reinfection.MethodsWe used next generation sequencing (NGS) to explore if cases with two positive real time RT-PCR tests > 90 days apart were infected with a different SARS-CoV-2 variant. Cases with confirmed reinfection between August 1st and October 31st, 2021 (the Delta wave) in Slovenia were matched 1:4 by age, sex and timeframe (week of positive test) with individuals with primary infection. Sociodemographic and epidemiologic data, vaccination status, and data on hospitalization and outcome of infection were retrieved from several centralized and standardized national databases. Additional epidemiologic surveys were performed on a limited number of cases and controls.ResultsWe identified 628 cases of genetically confirmed reinfection during the study period and matched them with 2,512 control subjects with Delta primary infection. Primary infections in individuals with reinfection were mainly caused by B.1.258.17 (51.1%), followed by B.1.1.7 (15.1%) and reinfection was detected on average 271 days after primary infection (range 101–477 days). Our results show a substantially lower probability of hospitalization in cases with reinfection compared with controls (OR: 0.21, p = 0.017), but no significant difference was observed in intensive care unit admission and deaths. We observed a significantly lower proportion of vaccinated individuals among cases compared to controls (4.5% vs. 28.2%), suggesting that hybrid immunity leads to lower probability of reinfection. Detailed analysis of the temporal distribution of variants, responsible for reinfections, showed no significant differences in reinfection potential.ConclusionReinfection with the SARS-CoV-2 Delta variant resulted in fewer hospitalizations compared to the primary Delta infection, suggesting that primary infection may, to some extent, produce at least short lasting protective immunity. This study provides additional insight into the reinfection dynamics that may allow appropriate public health measures to be taken in subsequent waves of the COVID-19 pandemic. |
| first_indexed | 2024-04-12T00:55:06Z |
| format | Article |
| id | doaj.art-c916776e158c4facabbd76881826ef7e |
| institution | Directory Open Access Journal |
| issn | 2296-858X |
| language | English |
| last_indexed | 2024-04-12T00:55:06Z |
| publishDate | 2022-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Medicine |
| spelling | doaj.art-c916776e158c4facabbd76881826ef7e2022-12-22T03:54:38ZengFrontiers Media S.A.Frontiers in Medicine2296-858X2022-10-01910.3389/fmed.2022.962653962653Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control studyAlen Suljič0Maja Sočan1Maja Mrzel2Maja M. Lunar3Miša Korva4Alenka Štorman5Katarina Prosenc6Sandra Janežič7Tjaša Žohar-Čretnik8Tina Zupanič9Mario Poljak10Tatjana Avšič-Županc11Faculty of Medicine, Institute of Microbiology and Immunology, University of Ljubljana, Ljubljana, SloveniaNational Institute of Public Health, Ljubljana, SloveniaNational Institute of Public Health, Ljubljana, SloveniaFaculty of Medicine, Institute of Microbiology and Immunology, University of Ljubljana, Ljubljana, SloveniaFaculty of Medicine, Institute of Microbiology and Immunology, University of Ljubljana, Ljubljana, SloveniaNational Laboratory of Health, Environment, and Food, Maribor, SloveniaNational Laboratory of Health, Environment, and Food, Maribor, SloveniaNational Laboratory of Health, Environment, and Food, Maribor, SloveniaNational Laboratory of Health, Environment, and Food, Maribor, SloveniaNational Institute of Public Health, Ljubljana, SloveniaFaculty of Medicine, Institute of Microbiology and Immunology, University of Ljubljana, Ljubljana, SloveniaFaculty of Medicine, Institute of Microbiology and Immunology, University of Ljubljana, Ljubljana, SloveniaBackgroundSARS-CoV-2 infection does not confer long immunity. However, studies suggest that prior infection is associated with lower risk of reinfection and milder outcomes of recurrent infections. The aims of this retrospective observational case-control study were to describe the clinical and molecular characteristics of genetically confirmed Delta reinfection cases and to assess the potential protective role of preceding infection on the severity of reinfection.MethodsWe used next generation sequencing (NGS) to explore if cases with two positive real time RT-PCR tests > 90 days apart were infected with a different SARS-CoV-2 variant. Cases with confirmed reinfection between August 1st and October 31st, 2021 (the Delta wave) in Slovenia were matched 1:4 by age, sex and timeframe (week of positive test) with individuals with primary infection. Sociodemographic and epidemiologic data, vaccination status, and data on hospitalization and outcome of infection were retrieved from several centralized and standardized national databases. Additional epidemiologic surveys were performed on a limited number of cases and controls.ResultsWe identified 628 cases of genetically confirmed reinfection during the study period and matched them with 2,512 control subjects with Delta primary infection. Primary infections in individuals with reinfection were mainly caused by B.1.258.17 (51.1%), followed by B.1.1.7 (15.1%) and reinfection was detected on average 271 days after primary infection (range 101–477 days). Our results show a substantially lower probability of hospitalization in cases with reinfection compared with controls (OR: 0.21, p = 0.017), but no significant difference was observed in intensive care unit admission and deaths. We observed a significantly lower proportion of vaccinated individuals among cases compared to controls (4.5% vs. 28.2%), suggesting that hybrid immunity leads to lower probability of reinfection. Detailed analysis of the temporal distribution of variants, responsible for reinfections, showed no significant differences in reinfection potential.ConclusionReinfection with the SARS-CoV-2 Delta variant resulted in fewer hospitalizations compared to the primary Delta infection, suggesting that primary infection may, to some extent, produce at least short lasting protective immunity. This study provides additional insight into the reinfection dynamics that may allow appropriate public health measures to be taken in subsequent waves of the COVID-19 pandemic.https://www.frontiersin.org/articles/10.3389/fmed.2022.962653/fullSARS-CoV-2COVID-19reinfectionDelta variantNGSgenetically confirmed variant |
| spellingShingle | Alen Suljič Maja Sočan Maja Mrzel Maja M. Lunar Miša Korva Alenka Štorman Katarina Prosenc Sandra Janežič Tjaša Žohar-Čretnik Tina Zupanič Mario Poljak Tatjana Avšič-Županc Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study Frontiers in Medicine SARS-CoV-2 COVID-19 reinfection Delta variant NGS genetically confirmed variant |
| title | Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study |
| title_full | Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study |
| title_fullStr | Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study |
| title_full_unstemmed | Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study |
| title_short | Milder outcomes of SARS-CoV-2 genetically confirmed reinfections compared to primary infections with the delta variant: A retrospective case-control study |
| title_sort | milder outcomes of sars cov 2 genetically confirmed reinfections compared to primary infections with the delta variant a retrospective case control study |
| topic | SARS-CoV-2 COVID-19 reinfection Delta variant NGS genetically confirmed variant |
| url | https://www.frontiersin.org/articles/10.3389/fmed.2022.962653/full |
| work_keys_str_mv | AT alensuljic milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT majasocan milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT majamrzel milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT majamlunar milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT misakorva milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT alenkastorman milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT katarinaprosenc milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT sandrajanezic milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT tjasazoharcretnik milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT tinazupanic milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT mariopoljak milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy AT tatjanaavsiczupanc milderoutcomesofsarscov2geneticallyconfirmedreinfectionscomparedtoprimaryinfectionswiththedeltavariantaretrospectivecasecontrolstudy |