Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States
Three safe and effective vaccines against SARS-CoV-2 have played a major role in combating COVID-19 in the United States. However, the effectiveness of these vaccines and vaccination programs has been challenged by the emergence of new SARS-CoV-2 variants of concern. A new mathematical model is form...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
AIMS Press
2023-01-01
|
| Series: | Mathematical Biosciences and Engineering |
| Subjects: | |
| Online Access: | https://www.aimspress.com/article/doi/10.3934/mbe.2023009?viewType=HTML |
| _version_ | 1828143023118090240 |
|---|---|
| author | Salman Safdar Calistus N. Ngonghala Abba B. Gumel |
| author_facet | Salman Safdar Calistus N. Ngonghala Abba B. Gumel |
| author_sort | Salman Safdar |
| collection | DOAJ |
| description | Three safe and effective vaccines against SARS-CoV-2 have played a major role in combating COVID-19 in the United States. However, the effectiveness of these vaccines and vaccination programs has been challenged by the emergence of new SARS-CoV-2 variants of concern. A new mathematical model is formulated to assess the impact of waning and boosting of immunity against the Omicron variant in the United States. To account for gradual waning of vaccine-derived immunity, we considered three vaccination classes that represent high, moderate and low levels of immunity. We showed that the disease-free equilibrium of the model is globally-asymptotically, for two special cases, if the associated reproduction number is less than unity. Simulations of the model showed that vaccine-derived herd immunity can be achieved in the United States via a vaccination-boosting strategy which entails fully vaccinating at least 59% of the susceptible populace followed by the boosting of about 72% of the fully-vaccinated individuals whose vaccine-derived immunity has waned to moderate or low level. In the absence of boosting, waning of immunity only causes a marginal increase in the average number of new cases at the peak of the pandemic, while boosting at baseline could result in a dramatic reduction in the average number of new daily cases at the peak. Specifically, for the fast immunity waning scenario (where both vaccine-derived and natural immunity are assumed to wane within three months), boosting vaccine-derived immunity at baseline reduces the average number of daily cases at the peak by about 90% (in comparison to the corresponding scenario without boosting of the vaccine-derived immunity), whereas boosting of natural immunity (at baseline) only reduced the corresponding peak daily cases (in comparison to the corresponding scenario without boosting of natural immunity) by approximately 62%. Furthermore, boosting of vaccine-derived immunity is more beneficial (in reducing the burden of the pandemic) than boosting of natural immunity. Finally, boosting vaccine-derived immunity increased the prospects of altering the trajectory of COVID-19 from persistence to possible elimination. |
| first_indexed | 2024-04-11T19:50:15Z |
| format | Article |
| id | doaj.art-5c6161f4c98249dbbb29cdacd0e80601 |
| institution | Directory Open Access Journal |
| issn | 1551-0018 |
| language | English |
| last_indexed | 2024-04-11T19:50:15Z |
| publishDate | 2023-01-01 |
| publisher | AIMS Press |
| record_format | Article |
| series | Mathematical Biosciences and Engineering |
| spelling | doaj.art-5c6161f4c98249dbbb29cdacd0e806012022-12-22T04:06:19ZengAIMS PressMathematical Biosciences and Engineering1551-00182023-01-0120117821210.3934/mbe.2023009Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United StatesSalman Safdar0Calistus N. Ngonghala1Abba B. Gumel 21. School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ 85287, USA2. Department of Mathematics, University of Florida, Gainesville, FL 32611, USA 3. Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA4. Department of Mathematics, University of Maryland College Park, MD 20742, USA 5. Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria 0002, South AfricaThree safe and effective vaccines against SARS-CoV-2 have played a major role in combating COVID-19 in the United States. However, the effectiveness of these vaccines and vaccination programs has been challenged by the emergence of new SARS-CoV-2 variants of concern. A new mathematical model is formulated to assess the impact of waning and boosting of immunity against the Omicron variant in the United States. To account for gradual waning of vaccine-derived immunity, we considered three vaccination classes that represent high, moderate and low levels of immunity. We showed that the disease-free equilibrium of the model is globally-asymptotically, for two special cases, if the associated reproduction number is less than unity. Simulations of the model showed that vaccine-derived herd immunity can be achieved in the United States via a vaccination-boosting strategy which entails fully vaccinating at least 59% of the susceptible populace followed by the boosting of about 72% of the fully-vaccinated individuals whose vaccine-derived immunity has waned to moderate or low level. In the absence of boosting, waning of immunity only causes a marginal increase in the average number of new cases at the peak of the pandemic, while boosting at baseline could result in a dramatic reduction in the average number of new daily cases at the peak. Specifically, for the fast immunity waning scenario (where both vaccine-derived and natural immunity are assumed to wane within three months), boosting vaccine-derived immunity at baseline reduces the average number of daily cases at the peak by about 90% (in comparison to the corresponding scenario without boosting of the vaccine-derived immunity), whereas boosting of natural immunity (at baseline) only reduced the corresponding peak daily cases (in comparison to the corresponding scenario without boosting of natural immunity) by approximately 62%. Furthermore, boosting of vaccine-derived immunity is more beneficial (in reducing the burden of the pandemic) than boosting of natural immunity. Finally, boosting vaccine-derived immunity increased the prospects of altering the trajectory of COVID-19 from persistence to possible elimination.https://www.aimspress.com/article/doi/10.3934/mbe.2023009?viewType=HTMLcovid-19sars-cov-2omicronvaccinationwaning and boosting immunityreproduction numbervaccine-derived herd immunity |
| spellingShingle | Salman Safdar Calistus N. Ngonghala Abba B. Gumel Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States Mathematical Biosciences and Engineering covid-19 sars-cov-2 omicron vaccination waning and boosting immunity reproduction number vaccine-derived herd immunity |
| title | Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States |
| title_full | Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States |
| title_fullStr | Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States |
| title_full_unstemmed | Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States |
| title_short | Mathematical assessment of the role of waning and boosting immunity against the BA.1 Omicron variant in the United States |
| title_sort | mathematical assessment of the role of waning and boosting immunity against the ba 1 omicron variant in the united states |
| topic | covid-19 sars-cov-2 omicron vaccination waning and boosting immunity reproduction number vaccine-derived herd immunity |
| url | https://www.aimspress.com/article/doi/10.3934/mbe.2023009?viewType=HTML |
| work_keys_str_mv | AT salmansafdar mathematicalassessmentoftheroleofwaningandboostingimmunityagainsttheba1omicronvariantintheunitedstates AT calistusnngonghala mathematicalassessmentoftheroleofwaningandboostingimmunityagainsttheba1omicronvariantintheunitedstates AT abbabgumel mathematicalassessmentoftheroleofwaningandboostingimmunityagainsttheba1omicronvariantintheunitedstates |