Epidemiological impact of prioritising SARS-CoV-2 vaccination by antibody status: mathematical modelling analyses

Ayoub, Houssein H.; Chemaitelly, Hiam; Makhoul, Monia; Kanaani, Zaina Al; Kuwari, Einas Al; Butt, Adeel A.; Coyle, Peter; Jeremijenko, Andrew; Kaleeckal, Anvar Hassan; Latif, Ali Nizar; Shaik, Riyazuddin Mohammad; Rahim, Hanan F. Abdul; Nasrallah, Gheyath K.; Yassine, Hadi M.; Al‐Kuwari, Mohamed Ghaith; Romaihi, Hamad Eid Al; Al-Thani, Mohamed H.; Bertollini, Roberto; Khal, Abdullatif Al; Abu‐Raddad, Laith J.

doi:10.1136/bmjinnov-2021-000677

Cited by 29 publications

(67 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The tested population is broadly representative of the urban population of Qatar [17], but less so of the craft and manual workers population who typically receive their primary healthcare at Qatar Red Crescent Society centers [14]. Qatar launched its vaccination campaign on December 21, 2020 [21], around the time this study was concluded (December 31, 2020), so very few individuals had been vaccinated at time of this study.…”

Section: Implications Of All the Available Evidencementioning

confidence: 99%

SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy

et al. 2021

Self Cite

View full text Add to dashboard Cite

Background Reinfection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented, raising public health concerns. SARS-CoV-2 reinfections were assessed in a cohort of antibody-positive persons in Qatar. Methods All SARS-CoV-2 antibody-positive persons from April 16 to December 31, 2020 with a PCR-positive swab ≥14 days after the first-positive antibody test were investigated for evidence of reinfection. Viral genome sequencing was conducted for paired viral specimens to confirm reinfection. Incidence of reinfection was compared to incidence of infection in the complement cohort of those who were antibody-negative. Findings Among 43,044 antibody-positive persons who were followed for a median of 16.3 weeks (range: 0–34.6), 314 individuals (0.7%) had at least one PCR positive swab ≥14 days after the first-positive antibody test. Of these individuals, 129 (41.1%) had supporting epidemiological evidence for reinfection. Reinfection was next investigated using viral genome sequencing. Applying the viral-genome-sequencing confirmation rate, the incidence rate of reinfection was estimated at 0.66 per 10,000 person-weeks (95% CI: 0.56–0.78). Incidence rate of reinfection versus month of follow-up did not show any evidence of waning of immunity for over seven months of follow-up. Meanwhile, in the complement cohort of 149,923 antibody-negative persons followed for a median of 17.0 weeks (range: 0–45.6), incidence rate of infection was estimated at 13.69 per 10,000 person-weeks (95% CI: 13.22–14.14). Efficacy of natural infection against reinfection was estimated at 95.2% (95% CI: 94.1–96.0%). Reinfections were less severe than primary infections. Only one reinfection was severe, two were moderate, and none were critical or fatal. Most reinfections (66.7%) were diagnosed incidentally through random or routine testing, or through contact tracing. Interpretation Reinfection is rare in the young and international population of Qatar. Natural infection appears to elicit strong protection against reinfection with an efficacy ~95% for at least seven months. Funding Biomedical Research Program, the Biostatistics, Epidemiology, and Biomathematics Research Core, and the Genomics Core, all at Weill Cornell Medicine-Qatar, the Ministry of Public Health, Hamad Medical Corporation, and the Qatar Genome Programme.

show abstract

Section: Implications Of All the Available Evidencementioning

confidence: 99%

SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Further background on Qatar's epidemic, such as on reinfections 13,14 , national seroprevalence surveys 17,31-33 , RT-qPCR surveys 17 , and other epidemiological studies can be found in previous publications on this epidemic 4,5,11,17,18, [34][35][36][37][38][39][40] .…”

Section: Infectiousness Of Bnt162b2-vaccine Breakthrough Infectionsmentioning

confidence: 99%

Effect of vaccination and of prior infection on infectiousness of vaccine breakthrough infections and reinfections

Abu‐Raddad

Chemaitelly

Ayoub

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

SARS-CoV-2 breakthrough infections in vaccinated individuals and in those who had a prior infection have been observed globally, but the transmission potential of these infections is unknown. The RT-qPCR cycle threshold (Ct) value is inversely correlated with viral load and culturable virus. Here, we investigated differences in RT-qPCR Ct values across Qatar national cohorts of primary infections, reinfections, BNT162b2 (Pfizer-BioNTech) breakthrough infections, and mRNA-1273 (Moderna) breakthrough infections. Through matched-cohort analyses of the randomly diagnosed infections, the mean Ct value was higher in all cohorts of breakthrough infections compared to the cohort of primary infections in unvaccinated individuals. The Ct value was 1.3 (95% CI: 0.9-1.8) cycles higher for BNT162b2 breakthrough infections, 3.2 (95% CI: 1.8-4.5) cycles higher for mRNA-1273 breakthrough infections, and 4.0 (95% CI: 3.4-4.6) cycles higher for reinfections in unvaccinated individuals. Assuming a linear relationship between viral load and infectiousness, these differences imply that breakthrough infections are at least 50% less infectious than primary infections in unvaccinated individuals. Public health benefits of vaccination may have been underestimated, as COVID-19 vaccines not only protect against acquisition of infection, but also appear to protect against transmission of infection.

show abstract

“…We adapted an existing mathematical model that investigates the generic population-level impact of SARS-CoV-2 vaccination and extended it to be applied to Lebanon [ 18 , 19 , 20 ]. This is a deterministic age-structured Susceptible-Exposed-Infectious-Recovered (SEIR) model that stratifies the population into compartments reflecting their vaccination status, age group, infection status, infection stage, and disease stage.…”

Section: Methodsmentioning

confidence: 99%

Modeling the Impact of COVID-19 Vaccination in Lebanon: A Call to Speed-Up Vaccine Roll Out

et al. 2021

Self Cite

View full text Add to dashboard Cite

Four months into the SARS-CoV-2 vaccination campaign, only 10.7% of the Lebanese population have received at least one dose, raising serious concerns over the speed of vaccine roll-out and its impact in the event of a future surge. Using mathematical modeling, we assessed the short-term impact of various vaccine roll-out scenarios on SARS-CoV-2 epidemic course in Lebanon. At current population immunity levels, estimated by the model at 40% on 15 April 2021, a large epidemic wave is predicted if all social distancing restrictions are gradually eased and variants of concern are introduced. Reaching 80% vaccine coverage by the end of 2021 will flatten the epidemic curve and will result in a 37% and 34% decrease in the peak daily numbers of severe/critical disease cases and deaths, respectively; while reaching intermediate coverage of 40% will result in only a 10–11% decrease in each. Reaching 80% vaccine coverage by August would prevent twice as many severe/critical disease cases and deaths than if it were reached by December. Easing restrictions over a longer duration resulted in more favorable vaccination impact. In conclusion, for vaccination to have impact in the short-term, scale-up has to be rapid and reach high coverage (at least 70%), while sustaining social distancing measures during roll-out. At current vaccination pace, this is unlikely to be achieved. Concerted efforts need to be made to overcome local challenges and substantially scale up vaccination to avoid a surge that the country, with its multiple crises and limited health-care capacity, is largely unprepared for.

show abstract

Epidemiological impact of prioritising SARS-CoV-2 vaccination by antibody status: mathematical modelling analyses

Cited by 29 publications

References 36 publications

SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy

SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy

Effect of vaccination and of prior infection on infectiousness of vaccine breakthrough infections and reinfections

Modeling the Impact of COVID-19 Vaccination in Lebanon: A Call to Speed-Up Vaccine Roll Out

Contact Info

Product

Resources

About