Vaccine and prior SARS-CoV-2 infection confer long-lasting protection against omicron BA.5
Study in the population living in Portugal shows that immunity conferred by infection of people vaccinated against COVID-19 confers up to 8 months of protection against omicron BA.5
Peer-Reviewed PublicationIMAGE: ILLUSTRATION OF SARS-COV-2. view more
CREDIT: HELENA PINHEIRO, IMM
Vaccine and prior SARS-CoV-2 infection confer long-lasting protection against omicron BA.5
Study in the population living in Portugal shows that immunity conferred by infection of people vaccinated against COVID-19 confers up to 8 months of protection against omicron BA.5
A new study led by Luís Graça, group leader at the Instituto de Medicina Molecular João Lobo Antunes (iMM, Lisbon) and full professor at the Medical School of the University of Lisbon, and Manuel Carmo Gomes, associate professor with aggregation at the Faculty of Sciences of the University of Lisbon (Ciências ULisboa), both members of the Direção Geral de Saúde (DGS) Technical Committee for Vaccination against COVID-19 (CTVC), and published today in the scientific journal Lancet Infectious Diseases*, shows that the protection conferred by hybrid immunity against the SARS-CoV-2 subvariant omicron BA.5, obtained by the infection of vaccinated people, lasts for at least eight months after the first infection.
This study follows the results published in September by the same researchers in the New England Journal of Medicine** where they showed, by studying the widely vaccinated Portuguese population, that infection by the first omicron subvariants of SARS-CoV-2, circulating in January and February 2022, conferred considerable protection against the omicron BA.5 subvariant circulating in Portugal since June and which remains the predominant variant in many countries. However, the stability of the protection conferred by the so-called hybrid immunity, the immunity conferred by the combination of vaccination and infection, was not yet known.
"In September, we had observed that infection by the first omicron subvariants conferred protection for the BA.5 subvariant about four times higher than vaccinated people who were not infected on any occasion, showing the importance of hybrid immunity for protection against new infections. Now, we show that this protection conferred by vaccination together with previous infections is stable and maintained until at least eight months after the first infection", explains Luís Graça, co-leader of the study.
As in the previous study, the researchers used the national COVID-19 case registry until September 2022, which is especially comprehensive due to the legal requirement to register all cases of SARS-CoV-2 infection at the time to gain access to sick leave during mandatory isolation days. "We used the national COVID-19 case registry to obtain the information of all cases of SARS-CoV-2 infections in the population over 12 years old residing in Portugal. These data from the Portuguese population allows us to conclude about hybrid immunity because vaccination had already covered 98% of this population by the end of 2021. The virus variant of each infection was determined considering the date of infection and the dominant variant at that time", explains Manuel Carmo Gomes, co-leader of the study.
About the calculations performed with these data, João Malato, first author of the study, explains: "With these data, we calculated the relative risk of reinfection over time in people vaccinated with previous infections by the first omicron subvariants of SARS-CoV-2, allowing us to conclude on the level of protection against reinfection. We found that protection remains high 8 months after contact with the virus."
"The protection afforded by hybrid immunity is initially about 90%, reducing after 5 months to about 70%, and showing a tendency to stabilize at a value of around 65% after 8 months, compared to the protection in vaccinated persons that were never infected by the virus. These results show that hybrid immunity conferred by infection with previous subvariants of SARS-CoV-2 in vaccinated people is quite stable", adds Luís Graça about the protection conferred by hybrid immunity.
This study shows that infection by previous subvariants of the SARS-CoV-2 virus, which causes COVID-19, has the ability to confer additional protection compared to the protection conferred by vaccination alone, and that this protection is stable.
This work was developed at the Instituto de Medicina Molecular João Lobo Antunes (iMM, Lisboa) and the Direção Geral de Saúde, in colaboration with researchers from the Centro de Estatística e Aplicações da Universidade de Lisboa, the Faculdade de Ciências da Universidade de Lisboa and Los Alamos National Laboratory (USA). This work was funded by the Horizon 2020 research and innovationfrom the European Union, Fundação para a Ciência e a Tecnologia (FCT, Portugal) and the National Institute of Health.
* João Malato, Ruy M Ribeiro, Eugénia Fernandes, Pedro P Leite, Pedro Casaca, Carlos Antunes, Válter R Fonseca, Manuel Carmo Gomes, Luís Graça. (2022) Stability of hybrid vs. vaccine immunity against BA.5 infection over 8 months. Lancet Infectious Diseases.
** João Malato, Ruy M Ribeiro, Pedro P Leite, Pedro Casaca, Eugénia Fernandes, Carlos Antunes, Válter R Fonseca, Manuel C Gomes, Luís Graça. (2022) Risk of BA.5 Infection among Persons Exposed to Previous SARS-CoV-2 Variants. New England Journal of Medicine.387(10):953-954. Doi: 10.1056/NEJMc2209479.
JOURNAL
The Lancet Infectious Diseases
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Stability of hybrid versus vaccine immunity against BA.5 infection over 8 months
Mathematical model predicts long-term effectiveness of COVID-19 vaccine booster doses in different patient populations
Model also simulates how well vaccines would fare against potential future viral variants.
Peer-Reviewed PublicationKey Takeaways
- Scientists have designed a mathematical model that can predict COVID-19 vaccines’ effectiveness over the long term in healthy individuals and those who have cancer or suppressed immune responses
- The model also considers the potential of the vaccines—including new bivalent vaccines—for protecting against hypothetical future viral variants
BOSTON – Researchers have designed a mathematical model that can predict the course of vaccine-induced immunity against COVID-19 in different patient populations—including otherwise healthy individuals and those who have cancer or suppressed immune responses—over the long term.
The model, which was developed by a team led by investigators at Massachusetts General Hospital (MGH), a founding member of the Mass General Brigham healthcare system, in collaboration with scientists at the University of Cyprus, also makes predictions under potential future scenarios (such as the emergence of SARS-CoV-2 variants with greater immune evasion) and reveals the benefits of the new bivalent vaccines.
The model builds on the investigators’ previously developed mathematical framework that they used to understand why treatment responses vary widely among people with COVID-19 and to identify biological markers related to these different responses, published in PNAS in 2021.
In this latest work, which is also published in PNAS, the scientists addressed the need for predictions of vaccine effectiveness over time.
“We used this model to simulate how differences in viral, patient, and vaccine characteristics may affect COVID-19 outcomes,” says senior author Rakesh K. Jain, PhD, director of the E.L. Steele Laboratories for Tumor Biology at MGH and the Andrew Werk Cook Professor of Radiation Oncology at Harvard Medical School.
For example, the model incorporates different variants of SARS-CoV-2 (including hypothetical ones), original and bivalent forms of the vaccine, and different considerations for certain patients—such as interactions between the virus, immune cells, and tumor cells in individuals with cancer.
The model predicted that a booster dose of either the Pfizer-BioNTech or Moderna mRNA vaccines can induce robustly enhanced antibody- and immune cell–based responses against SARS-CoV-2 to provide sufficient protection for more than 1 year in healthy individuals.
However, the model suggested that for people with suppressed immune responses or those with cancer receiving immunosuppressive treatments, the booster effect may wane fairly quickly. These patients should therefore be given booster vaccines on a more frequent basis.
For people receiving the Johnson & Johnson/Janssen vector vaccine, additional booster doses should be considered for everyone. The analysis also revealed that the optimal schedule for vaccine booster doses is not the same for all SARS-CoV-2 variants.
“Our results could help inform the timing of booster vaccinations in individuals with different characteristics and comorbidities, as well as for novel viral variants,” says Jain.
“As we approach an endemic phase of SARS-CoV-2, a rational approach to vaccine booster utilization may help ensure equitable access to vaccines and help prevent further outbreaks and development of new variants.”
Co-corresponding authors are Lance L. Munn, MGH, and Triantafyllos Stylianopoulos, University of Cyprus. Other MGH authors are Chrysovalantis Voutouri, C. Corey Hardin, Vivek Naranbhai, Mohammad R. Nikmaneshi, Melin J. Khandekar, and Justin F. Gainor.
Jain’s research is supported by grants from National Institutes of Health, the National Foundation for Cancer Research, Jane’s Trust Foundation, Niles Albright Research Foundation and Harvard Ludwig Cancer Center. Munn’s research is supported by a National Institutes of Health grant. Stylianopoulos’s research is supported by the European Research Council and Cyprus Research and Innovation Foundation.
About the Massachusetts General Hospital
Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In July 2022, Mass General was named #8 in the U.S. News & World Report list of "America’s Best Hospitals." MGH is a founding member of the Mass General Brigham healthcare system.
JOURNAL
Proceedings of the National Academy of Sciences
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
People
ARTICLE TITLE
Mechanistic model for booster doses effectiveness in healthy, cancer and 3 immunosuppressed patients infected with SARS-CoV-2
ARTICLE PUBLICATION DATE
9-Jan-2023
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