Risk of SARS-CoV-2 Reinfection 3 Years after the Start of the Pandemic: A Population-Level Observational Study

The risk of SARS-CoV-2 reinfections changes as new variants emerge, but the follow-up time for most of the available evidence is shorter than two years. This study evaluated SARS-CoV-2 reinfection rates in the total population of an Italian province up to three years since the pandemic's start. This retrospective cohort study used official National Healthcare System data on SARS-CoV-2 testing and vaccinations, demographics, and hospitalizations in the Province of Pescara, Italy, from 2 March 2020 to 31 December 2022. A total of 6541 (5.4%) reinfections and 33 severe and 18 lethal COVID-19 cases were recorded among the 121,412 subjects who recovered from a primary infection. There were no severe events following reinfection in the young population, whereas 1.1% of reinfected elderly died. A significantly higher reinfection risk was observed among females; unvaccinated individuals; adults (30-59 y); and subjects with hypertension, COPD, and kidney disease. Up to three years after a primary SARS-CoV-2 infection, the majority of the population did not experience a reinfection. The risk of severe COVID-19 following a reinfection was very low for young and adult individuals but still high for the elderly. The subjects with hybrid immunity showed a lower reinfection risk than the unvaccinated.

Predictors of SARS-CoV-2 Infection and Severe and Lethal COVID-19 after Three Years of Follow-Up: A Population-Wide Study

In this cohort study, the general population of an Italian Province was followed for three years after the start of the pandemic, in order to identify the predictors of SARS-CoV-2 infection and severe or lethal COVID-19. All the National Healthcare System information on biographical records, vaccinations, SARS-CoV-2 swabs, COVID-19 cases, hospitalizations and co-pay exemptions were extracted from 25 February 2020 to 15 February 2023. Cox proportional hazard analysis was used to compute the relative hazards of infection and severe or lethal COVID-19, adjusting for age, gender, vaccine status, hypertension, diabetes, major cardiovascular diseases (CVD), chronic obstructive pulmonary disease (COPD), kidney disease or cancer. Among the 300,079 residents or domiciled citizens, 41.5% had ≥1 positive swabs during the follow-up (which lasted a mean of 932 days). A total of 3.67% of the infected individuals experienced severe COVID-19 (n = 4574) and 1.76% died (n = 2190). Females, the elderly and subjects with diabetes, CVD, COPD, kidney disease and cancer showed a significantly higher risk of SARS-CoV-2 infection. The likelihood of severe or lethal COVID-19 was >90% lower among the youngest, and all comorbidities were independently associated with a higher risk (ranging from +28% to +214%) of both outcomes. Two years after the start of the immunization campaign, the individuals who received ≥2 doses of COVID-19 vaccines still showed a significantly lower likelihood of severe or lethal disease, with the lowest risk observed among subjects who received at least one booster dose.

COVID-19 Vaccination Effectiveness in the General Population of an Italian Province: Two Years of Follow-Up

We carried out a cohort study on the overall population of the province of Pescara, Italy, to assess the real-world effectiveness of SARS-CoV-2 vaccination against infection, severe, or lethal COVID-19, two years after the start of the vaccination campaign. We included all the resident or domiciled subjects, and extracted the official demographic, vaccination, COVID-19, hospital and co-pay exemption datasets from 1 January 2021, up to 15 February 2023. Cox proportional hazards analyses were adjusted for gender, age, diabetes, hypertension, COPD, major cardio- and cerebrovascular events, cancer, and kidney diseases. Throughout the follow-up (466 days on average), 186,676 subjects received greater than or equal to three vaccine doses (of ChAdOx1 nCoV-19, BNT162b2, mRNA-1273, NVX-CoV2373, or JNJ-78436735), 47,610 two doses, 11,452 one dose, and 44,989 none. Overall, 40.4% of subjects were infected with SARS-CoV-2. Of them, 2.74% had severe or lethal (1.30%) COVID-19. As compared to the unvaccinated, the individuals who received greater than or equal to one booster dose showed a ≥85% lower risk of severe or lethal COVID-19. A massive impact of vaccination was found among the elderly: 22.0% of the unvaccinated, infected individuals died, as opposed to less than 3% of those who received greater than or equal to three vaccine doses. No protection against infection was observed, although this finding was certainly influenced by the Italian restriction policies to control the pandemic. Importantly, during the Omicron predominance period, only the group who received at least a booster dose showed a reduced risk of COVID-19-related death.

Risk of SARS-CoV-2 reinfection 18 months after first infection: population-level observational study

Background

Current data suggest that SARS-CoV-2 reinfections are rare. Uncertainties remain, however, on the duration of the natural immunity, its protection against Omicron variant, and on the impact of vaccination to reduce reinfection rates.

Methods

In this retrospective cohort analysis of the entire population of an Italian Region, we followed 1,293,941 subjects from the beginning of the pandemic to the current scenario of Omicron predominance (up to mid-February 2022). We assessed the proportion of reinfections overall, and by demographic and clinical characteristics, time after primary infection, and predominant circulating variant. Cox proportional hazard analysis was used to compute the relative hazards of reinfection.

Results

After an average of 277 days, we recorded 729 reinfections among 119,266 previously infected subjects (overall rate: 6.1‰), eight COVID-19-related hospitalizations (7/100,000), and two deaths. Importantly, the incidence of reinfection did not vary substantially over time: after 18-22 months from the primary infection, the reinfection rate was still 6.7‰, suggesting that protection conferred by natural immunity may last beyond 12 months. The risk of reinfection was significantly higher among females, unvaccinated subjects, and during the Omicron wave.

Conclusions

This study confirms and expands previous findings reporting a low risk of SARS-CoV-2 reinfection, and a very low risk of severe or lethal COVID-19 for those who recovered from primary infection, suggesting that the protection conferred by the natural immunity lasts beyond 12 months. Although the marked increase of the reinfection rates during the Omicron wave is concerning, the risk of a secondary severe disease or death remained close to zero. Vaccines were able to significantly reduce the likelihood of reinfection in both pre-Omicron and Omicron waves, although the risk-benefit profile of multiple vaccine doses for this population should be carefully evaluated.

Key messages

• After primary infection, the risk of SARS-CoV-2 reinfection and of severe/lethal COVID-19 was low, suggesting that natural immunity lasts beyond 12 months.

• Despite increasing reinfection rates with Omicron, the risk of a secondary severe/lethal disease was close to zero, and vaccines reduced the likelihood of reinfection before and during Omicron waves.

C64 UNMASKING THE PREVALENCE OF AMYLOID CARDIOMYOPATHY IN THE REAL WORLD: RESULTS FROM PHASE 2 OF AC–TIVE STUDY, AN ITALIAN NATIONWIDE SURVEY

Background

Clinicians need to identify patients with amyloid cardiomyopathy (AC) at an early stage, due to the availability of disease–modifying therapies. Some echocardiographic findings may rise the suspicion of AC, also in patients with mild or no symptoms, addressing second level diagnostic tests.

Aim

To investigate the prevalence of AC in consecutive patients ≥55 years undergoing clinically indicated, routine transthoracic echocardiogram in Italy and presenting echocardiographic signs suggestive of AC.

Methods

This is a prospective multicentric study conducted in Italy. It comprises two phases: 1) a recording phase consisting in a national survey on prevalence of possible echocardiographic red flags of AC in consecutive unselected patients ≥55 years undergoing routine echocardiogram (previously published) and 2) an AC diagnostic phase involving a diagnostic work–up for AC to investigate AC prevalence among patients with at least one echocardiographic red flag (herein presented). Patients that in Phase 1 presented an “AC suggestive” echocardiogram (i.e., at least one red flag of AC in hypertrophic, non–dilated left ventricles with preserved ejection fraction) underwent clinical evaluation, blood and urine tests and scintigraphy with bone tracer. Diagnosis of transthyretin related–AC (ATTR–AC) was made in presence of grade 2–3 Perugini uptake at scintigraphy and absence of monoclonal protein. The study was registered at ClinicalTrials.gov (#NCT04738266).

Results

Of the 5315 screened echocardiograms, 381 exams (7.2%) were classified as “AC suggestive” and proceeded to Phase 2. 217 patients completed Phase 2 investigations. Main reasons for the 164 non–entering patients into Phase 2 were death (n = 49) and refusal to participate (n = 66). A final diagnosis of AC was made in 62 patients with an estimated prevalence of 28,6% (95% CI: 22,5%–34,7%). ATTR–AC was diagnosed in 51 and AL–AC in 11 patients, ascertaining a prevalence of 23,5% (95% CI: 17,8%–29,2%) and 5,1% (95% CI: 2,2%–8,0%), respectively.

Conclusion

Among a cohort of consecutive unselected patients ≥55 years with echocardiographic findings suggestive of AC, the prevalence of AC ranged from 23% up to 35%. Although ATTR–AC was predominant, AL–AC was diagnosed in a significant number of cases. Echocardiography has a fundamental role in screening patients, raising the suspicion of disease and orienting diagnostic work–up for AC.

Risk of SARS-CoV-2 Reinfection 18 Months After Primary Infection: Population-Level Observational Study

Current data suggest that SARS-CoV-2 reinfections are rare. Uncertainties remain, however, on the duration of the natural immunity, its protection against Omicron variant, and on the impact of vaccination to reduce reinfection rates. In this retrospective cohort analysis of the entire population of an Italian region, we followed 1,293,941 subjects from the beginning of the pandemic to the current scenario of Omicron predominance (up to mid-February 2022). After an average of 277 days, we recorded 729 reinfections among 119,266 previously infected subjects (overall rate: 6.1‰), eight COVID-19-related hospitalizations (7/100,000), and two deaths. Importantly, the incidence of reinfection did not vary substantially over time: after 18-22 months from the primary infection, the reinfection rate was still 6.7‰, suggesting that protection conferred by natural immunity may last beyond 12 months. The risk of reinfection was significantly higher among females, unvaccinated subjects, and during the Omicron wave.

Development of a web platform for COVID-19 integrated care: an experience from an Italian Region

Issue

After the announcement of Public Health Emergency of International Concern about COVID19 by WHO, health authorities need to implement strategies to face the emergency. These responses included early diagnosis, patient isolation, quarantine and symptomatic monitoring of contacts. In this context, integrated care and telemedicine are the best instruments for COVID management.

Description of the problem

The COVID19 epidemic needs a real time integration of epidemiological, clinical and laboratoristic data, in order to better manage patients and to improve public health surveillance. Based on a tool previosly used by GPs for flu vaccination and diabetes integrated care, the Local Health Authority of Pescara, Abruzzo Region, Italy, developed a web-based platform (QuickwebConnect), accessible to public health practitioners (PHP), GPs, infectious diseases physicians and laboratories, in order to integrate information about COVID19 patients. This platform contain individual-level information on patients with laboratory-confirmed COVID19, symptoms, reported onset dates, and basic demographics. Information are in real time accessible to all actors involved in the process. In addition, GPs can use this tool to directly book diagnostic tests for symptomatic or suspected patients.

Results

With the use of this platform, the management of pandemic emergency was improved, allowing direct management of epidemic data both at person and population level. The real time evaluation of clinical and epidemiological data improved patients care, clinical survellance of COVID19 contacts and development of tailored preventive measure in areas with high incidence.

Lessons

COVID19 patients care need to be quick, needing the integrate support of different actors. In addition, public health actions have to be supported by strong data. The use of a cost-effective web platform allow physician and PHP to better manage patiens and develope focused interventions.

Key messages

Integrated care and telemedicine are best instruments for COVID management. The real time evaluation of data aimed to develop tailored preventive measure.

Rate of reinfections after SARS-CoV-2 primary infection in the population of an Italian province: a cohort study

BACKGROUND

Current data suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfections are rare, but no information are available on minors and after 12 months of follow-up.

METHODS

This retrospective cohort study included all the population of an Italian Province, diagnosed with a SARS-CoV-2 infection from March 2020 to May 2021. The primary outcome was the incidence of a reinfection, defined as a new positive polymerase chain reaction (PCR) test occurring ≥90 days after complete resolution of the first infection, and data were retrieved from the official datasets (coronavirus disease 2019 [COVID-19], demographic, hospital and co-pay exemption) of the Local Health Unit (LHU) of Pescara.

RESULTS

After an average of 201 days of follow-up (max. 414), we recorded 24 reinfections ≥90 days after the resolution of the first 7173 infections (0.33%). Four reinfections required hospitalization, one was lethal. Most of the reinfections (n = 13) occurred 6-9 months after the resolution of the first infection; no new infection was detected 12 or more months later and among the 832 minors.

CONCLUSIONS

This study confirms previous findings on a low risk of SARS-CoV-2 reinfection. If confirmed, these findings suggest that more targeted restriction policies can be applied to the subjects that recovered after a first infection.

Interim Estimates of COVID-19 Vaccine Effectiveness in a Mass Vaccination Setting: Data from an Italian Province

This retrospective cohort study compared the rates of virologically-confirmed SARS-CoV-2 infections, symptomatic or lethal COVID-19 among the residents of the Italian province of Pescara who received one or two doses of COVID-19 vaccines, versus the unvaccinated. The official data of the National Health System were used, and a total of 69,539 vaccinated adults were compared with 175,687 unvaccinated. Among the subjects who received at least one vaccine dose, 85 infections (0.12%), 18 severe and 3 lethal COVID-19 cases were recorded after an average follow-up of 38 days. Among the unvaccinated, the numbers were 6948 (4.00%), 933 (0.53%) and 241 (0.14%), respectively. The serious adverse event reports-yet unconfirmed-were 24 out of 102,394 administered doses. In a Cox model, adjusting for age, gender, and selected comorbidities, the effectiveness of either BNT162b2, ChAdOx1 nCoV-19 or mRNA-1273 vaccines was higher than 95% in preventing infections (mostly due to B.1.1.7 variant), symptomatic or lethal COVID-19. No differences were observed across genders, and among the 691 subjects who received the second dose of vaccine later than the recommended date. Although preliminary, these findings support current immunization policies and may help reducing vaccine hesitancy.

A large food-borne outbreak of campylobacteriosis in kindergartens and primary schools in Pescara, Italy, May-June 2018

Introduction. In May-June 2018, an outbreak of campylobacteriosis involved students and school staff from kindergartens and primary schools in Pescara, southern Italy.Aim. We present details of the epidemiological and microbiological investigation, and the findings of the analytical study, as well as the implemented control measures.Methodology. To identify possible risk factors associated with the observed outbreak, a case control study was conducted using a questionnaire to collect information on the date of symptoms onset, type and duration of symptoms, type of healthcare contact, school attendance, and food items consumed at school lunches during the presumed days of exposure. Attack rates were calculated for each date and school. Logistic regression models were used to estimate the odds ratios of being a case and the odds of illness by food items consumed, respectively. Moreover, we carried out a comparative genomic analysis using whole genome multilocus sequence typing (wgMLST) of Campylobacter jejuni strains isolated during the outbreak investigation to identify the source of the outbreak.Results. Overall, 222 probable cases from 21 schools were identified, and C. jejuni was successfully isolated from 60 patients. The meals in the schools involved were provided by two cooking centres managed by a joint venture between two food companies. Environmental and food sampling, epidemiological and microbiological analyses, as well as a case control study with 176 cases and 62 controls from the same schools were performed to identify the source of the outbreak. The highest attack rate was recorded among those having lunch at school on 29 May (7.8 %), and the most likely exposure was 'caciotta' cheese (odds ratio 2.40, 95 % confidence interval 1.10-5.26, P=0.028). C. jejuni was isolated from the cheese, and wgMLST showed that the human and cheese isolates belonged to the same genomic cluster, confirming that the cheese was the vehicle of the infection.Conclusion. It is plausible that a failure of the pasteurization process contributed to the contamination of the cheese batches. Timely suspension of the catering service and summer closure of the schools prevented further spread.

[Prevention in regional policy]

Prevention, safety and health promotion represent fondamental issues in the Regional policy. With this regard, the implementation of the Regional policy has been thought as the promotion of an integrated system which links different fields such as health, work-related information and education, job orientation and work in general. It is recommended that a good standard of prevention is achieved through the synergic actions and the collaborations among all the different actors playing a role in safety and prevention in workplace, including occupational physicians, safety and prevention operators, safety representatives for workers, trade unions, employers associations and public institutions. It is also necessary to adopt a strategy in order to decrease the number of misdiagnosed occupational diseases as well as to promote the "culture of safety in workplaces", increasing the awareness of all figures, with special focus on employers category. All this has to be set in the new scenario of the nowadays work characterized by the progressive increase of atypical job contracts, renewing the emphasis on the necessity of keeping joined "the right to a job with the right to health".

[Torsion of a wandering spleen: ultrasonography and computer tomography in conservative treatment. A case report]

Torsion of the vascular pedicle in a wandering spleen is treated conservatively in most of the cases whenever irreversible necrosis of the organ is not occurred. A case, in a 10 years old boy, is reported. The patient was admitted for acute abdominal pain and was investigated by ultrasounds, which showed an ectopic enlarged spleen at the left flank, without any sign of parenchymal necrosis. A spiral contrast enhanced angio-CT scan confirmed the diagnosis and demonstrated multiple ischemic lesions of splenic pulp mainly at the lower pole. The child was treated with splenopexy followed by un uneventful recovery. CT scan study in cases of torsion of a wandering spleen is of great help in confirming clinical and ultrasonographic diagnosis and in demonstrating the amount of ischemic lesion of the organ before surgical exploration.

Preliminary report: Amino acid profile in platelets of diabetic patients

Platelet levels of 19 amino acids were measured in 20 outpatients with type 1 (age [mean +/- SE], 35.5 +/- 2.0 years) and 27 with type 2 (age, 58.4 +/- 1.4 years) diabetes, and 20 young (age 33.7 +/- 1.3 years) and 20 older (age 57.4 +/- 1.5 years) healthy volunteers. Platelet levels of most amino acids tended to be lower in patients with type 1 diabetes than in healthy controls. In particular, asparagine, glycine, taurine, alanine, valine, cysteine, leucine, phenylalanine, and lysine levels, expressed as nmol/10(8) platelets, were significantly lower. Only taurine significantly decreased in patients with type 2 diabetes, whereas threonine, alanine, and isoleucine increased.

Taurine and osmoregulation: platelet taurine content, uptake, and release in type 2 diabetic patients

In this study, plasma and platelet taurine content and fluxes were determined in 38 type 2 diabetic patients and in 26 healthy control subjects. Taurine levels in diabetic patients were significantly lower than in control subjects both in plasma (32.1 v 48.6 micromol/L, P = .000) and platelets (148 v 183 nmol/mg protein, P = .043). Platelet taurine uptake in diabetic patients was significantly reduced (321.2 v 524.9 pmol total taurine 10(8) platelet(-1) min(-20), P = .000), whereas taurine release increased in comparison to healthy controls (38.7 v 29.5% of platelet 3H taurine at the start of incubation, P = .000). These results may reflect modified systems of taurine carriers or a compensatory mechanism in response to an increase of other organic osmolytes.

Thyroxine effects on polyamine metabolism in rat cerebellum and brain cortex during postnatal development

Polyamine content, ODC and SAMDC activities have been assayed in cerebellum and brain cortex of hyperthyroid rats during postnatal development. Daily thyroxine treatment induced ODC and SAMDC biosynthesis in early periods of postnatal life in both cerebellum and brain cortex. In addition, in comparison to controls an increase in spermidine and spermine content was shown to occur in hyperthyroid rats. A functional correlation between polyamine content and nucleic acids could explain a correlation between polyamine biosynthesis and morphofunctional maturative processes in the brain.

A decrease in guanylate cyclase activity in some tissues of C3H/HeJ mice with retinal dystrophy

Guanylate cyclase activity was assayed in homogenates, in particulate and soluble fractions from retina, cerebellum, cerebral cortex and adrenal gland of adult C3H/HeJ mice with a dystrophic retinopathy. In comparison to control mice (DBA/1J), in C3H/HeJ strain a significant decrease in guanylate cyclase activity occurred in homogenates from retina, cerebellum and adrenal gland. In particular a significant decrease was found in particulate fraction of retina, in the soluble fraction of cerebral cortex and cerebellum and in both fractions of the adrenal gland. In contrast to the retina and cerebellum where guanylate cyclase activity in homogenates was found significantly decreased both in the male and female, in the cerebral cortex guanylate cyclase decreased in both sexes although in female this was more marked.