Observational studyThe Lancet. Infectious diseases2022
Persistence of protection against SARS-CoV-2 clinical outcomes up to 9 months since vaccine completion: a retrospective observational analysis in Lombardy, Italy.
Observational study in The Lancet. Infectious diseases, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
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Who cites it
12 citing papers in PubMed, 18 citations in OpenAlex.
- Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection by Type and Frequency of Vaccine: A Community-Based Case-Control Study.Journal of Korean medical science · 2024Article
- Estimating All-Cause Deaths Averted in the First Two Years of the COVID-19 Vaccination Campaign in Italy.Vaccines · 2024Article
- The Community Pharmacy as a Study Center for the Epidemiological Analysis of the Population Vaccination against SARS-CoV-2: Evaluation of Vaccine Safety and Pharmaceutical Service.Pharmacy (Basel, Switzerland) · 2024Article
- The effectiveness of COVID-19 vaccines against severe cases and deaths in Brazil from 2021 to 2022: a registry-based study.Lancet regional health. Americas · 2023Article
- Durability of Vaccine-Induced and Natural Immunity Against COVID-19: A Narrative Review.Infectious diseases and therapy · 2023Review
- Long-term adaptive response in COVID-19 vaccine recipients and the effect of a booster dose.Frontiers in immunology · 2023Article
- Assessing the Impact of Contact Tracing, Quarantine and Red Zone on the Dynamical Evolution of the Covid-19 Pandemic using the Cellular Automata Approach and the Resulting Mean Field System: A Case study in Mauritius.Applied mathematical modelling · 2022Article
- COVID-19 vaccine: what are we doing and what should we do?The Lancet. Infectious diseases · 2022Article
- Neutralizing Antibodies Responses against SARS-CoV-2 in a Sardinian Cohort Group Up to 9 Months after BNT162b2 Vaccination.Vaccines · 2022Article
- Eight Good Reasons for Careful Monitoring and Evaluation of the Vaccine Campaign against COVID-19: Lessons Learned through the Lombardy Experience for Dealing with Next Challenges.International journal of environmental research and public health · 2022Review
- Transmissibility, hospitalization, and intensive care admissions due to omicron compared to delta variants of SARS-CoV-2 in Catalonia: A cohort study and ecological analysis.Frontiers in public health · 2022Article
- Knocking on heaven's door: The gap between health institutions and academies in generating knowledge utilizing real-world data.Frontiers in public health · 2022Article
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Authors and funding
16 authors at 5 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundScarce information is available on the duration of the protective effect of COVID-19 vaccination against the risk of SARS-CoV-2 infection and its severe clinical consequences. We investigated the effect of time since vaccine completion on the SARS-CoV-2 infection and its severe forms.
methodsIn this retrospective observational analysis using the vaccination campaign integrated platform of the Italian region of Lombardy, 5 351 085 individuals aged 12 years or older who received complete vaccination from Jan 17 to July 31, 2021, were followed up from 14 days after vaccine completion until Oct 20, 2021. Changes over time in outcome rates (ie, SARS-CoV-2 infection and severe illness among vaccinated individuals) were analysed with age-period-cohort models. Trends in vaccine effectiveness (ie, outcomes comparison in vaccinated and unvaccinated individuals) were also measured.
findingsOverall, 14 140 infections and 2450 severe illnesses were documented, corresponding to incidence rates of 6·7 (95% CI 6·6-6·8) and 1·2 (1·1-1·2) cases per 10 000 person-months, respectively. From the first to the ninth month since vaccine completion, rates increased from 4·6 to 10·2 infections, and from 1·0 to 1·7 severe illnesses every 10 000 person-months. These figures correspond to relative reduction of vaccine effectiveness of 54·9% (95% CI 48·3-60·6) for infection and of 40·0% (16·2-57·0) for severe illness. The increasing infection rate was greater for individuals aged 60 years or older who received adenovirus-vectored vaccines (from 4·0 to 23·5 cases every 10 000 person-months). The increasing severe illness rates were similar for individuals receiving mRNA-based vaccines (from 1·1 to 1·5 every 10 000 person-months) and adenovirus-vectored vaccines (from 0·5 to 0·9 every 10 000 person-months).
interpretationAlthough the risk of infection after vaccination, and even more of severe illness, remains low, the gradual increase in clinical outcomes related to SARS-CoV-2 infection suggests that the booster campaign should be accelerated and that social and individual protection measures against COVID-19 spread should not be abandoned.
fundingNone.
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