Persistence of Protection Against SARS-CoV-2 Clinical Outcomes Up to 9 Months Since Vaccine Completion: a Retrospective Observational Analysis in Lombardy, Italy

Overview

Journal Lancet Infect Dis

Specialty Infectious Diseases

Date 2022 Jan 30

PMID 35093194

Authors

Giovanni Corrao

Matteo Franchi

Danilo Cereda

Francesco Bortolan

Alberto Zoli

Olivia Leoni

Catia Rosanna Borriello

Giulia Petra Della Valle

Marcello Tirani

Giovanni Pavesi

Antonio Barone

Michele Ercolanoni

Jose Jara

Massimo Galli

Guido Bertolaso

Giuseppe Mancia

Affiliations

Soon will be listed here.

Abstract

Background: Scarce 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.

Methods: In 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.

Findings: Overall, 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).

Interpretation: Although 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.

Funding: None.

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References

Ukey R, Bruiners N, Mishra H, Mishra P, McCloskey D, Onyuka A . Dichotomy between the humoral and cellular responses elicited by mRNA and adenoviral vector vaccines against SARS-CoV-2. BMC Med. 2022; 20(1):32. PMC: 8786593. DOI: 10.1186/s12916-022-02252-0. View

Dagan N, Barda N, Kepten E, Miron O, Perchik S, Katz M . BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Mass Vaccination Setting. N Engl J Med. 2021; 384(15):1412-1423. PMC: 7944975. DOI: 10.1056/NEJMoa2101765. View

Hall V, Foulkes S, Saei A, Andrews N, Oguti B, Charlett A . COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. Lancet. 2021; 397(10286):1725-1735. PMC: 8064668. DOI: 10.1016/S0140-6736(21)00790-X. View

Carstensen B . Age-period-cohort models for the Lexis diagram. Stat Med. 2006; 26(15):3018-45. DOI: 10.1002/sim.2764. View

Lopez Bernal J, Andrews N, Gower C, Gallagher E, Simmons R, Thelwall S . Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant. N Engl J Med. 2021; 385(7):585-594. PMC: 8314739. DOI: 10.1056/NEJMoa2108891. View

Voysey M, Clemens S, Madhi S, Weckx L, Folegatti P, Aley P . Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. Lancet. 2021; 397(10277):881-891. PMC: 7894131. DOI: 10.1016/S0140-6736(21)00432-3. View

Lopez Bernal J, Andrews N, Gower C, Robertson C, Stowe J, Tessier E . Effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines on covid-19 related symptoms, hospital admissions, and mortality in older adults in England: test negative case-control study. BMJ. 2021; 373:n1088. PMC: 8116636. DOI: 10.1136/bmj.n1088. View

Polack F, Thomas S, Kitchin N, Absalon J, Gurtman A, Lockhart S . Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. N Engl J Med. 2020; 383(27):2603-2615. PMC: 7745181. DOI: 10.1056/NEJMoa2034577. View

Voysey M, Clemens S, Madhi S, Weckx L, Folegatti P, Aley P . Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet. 2020; 397(10269):99-111. PMC: 7723445. DOI: 10.1016/S0140-6736(20)32661-1. View

10.

Tartof S, Slezak J, Fischer H, Hong V, Ackerson B, Ranasinghe O . Effectiveness of mRNA BNT162b2 COVID-19 vaccine up to 6 months in a large integrated health system in the USA: a retrospective cohort study. Lancet. 2021; 398(10309):1407-1416. PMC: 8489881. DOI: 10.1016/S0140-6736(21)02183-8. View

11.

Baraniuk C . How long does covid-19 immunity last?. BMJ. 2021; 373:n1605. DOI: 10.1136/bmj.n1605. View

12.

Thomas S, Moreira Jr E, Kitchin N, Absalon J, Gurtman A, Lockhart S . Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine through 6 Months. N Engl J Med. 2021; 385(19):1761-1773. PMC: 8461570. DOI: 10.1056/NEJMoa2110345. View

13.

Teyssou E, Delagreverie H, Visseaux B, Lambert-Niclot S, Brichler S, Ferre V . The Delta SARS-CoV-2 variant has a higher viral load than the Beta and the historical variants in nasopharyngeal samples from newly diagnosed COVID-19 patients. J Infect. 2021; 83(4):e1-e3. PMC: 8375250. DOI: 10.1016/j.jinf.2021.08.027. View

14.

Baden L, El Sahly H, Essink B, Kotloff K, Frey S, Novak R . Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine. N Engl J Med. 2020; 384(5):403-416. PMC: 7787219. DOI: 10.1056/NEJMoa2035389. View

15.

McDonald I, Murray S, Reynolds C, Altmann D, Boyton R . Comparative systematic review and meta-analysis of reactogenicity, immunogenicity and efficacy of vaccines against SARS-CoV-2. NPJ Vaccines. 2021; 6(1):74. PMC: 8116645. DOI: 10.1038/s41541-021-00336-1. View

16.

Bell A . Age period cohort analysis: a review of what we should and shouldn't do. Ann Hum Biol. 2020; 47(2):208-217. DOI: 10.1080/03014460.2019.1707872. View

17.

Ananth C, Keyes K, Wapner R . Pre-eclampsia rates in the United States, 1980-2010: age-period-cohort analysis. BMJ. 2013; 347:f6564. PMC: 3898425. DOI: 10.1136/bmj.f6564. View

18.

Parry H, Bruton R, Stephens C, Brown K, Amirthalingam G, Otter A . Differential immunogenicity of BNT162b2 or ChAdOx1 vaccines after extended-interval homologous dual vaccination in older people. Immun Ageing. 2021; 18(1):34. PMC: 8377354. DOI: 10.1186/s12979-021-00246-9. View

19.

Doria-Rose N, Suthar M, Makowski M, OConnell S, McDermott A, Flach B . Antibody Persistence through 6 Months after the Second Dose of mRNA-1273 Vaccine for Covid-19. N Engl J Med. 2021; 384(23):2259-2261. PMC: 8524784. DOI: 10.1056/NEJMc2103916. View

20.

Cohn B, Cirillo P, Murphy C, Krigbaum N, Wallace A . SARS-CoV-2 vaccine protection and deaths among US veterans during 2021. Science. 2021; 375(6578):331-336. PMC: 9836205. DOI: 10.1126/science.abm0620. View