Pietro Crovari

Safety and immunogenicity of an inactivated subunit influenza virus vaccine combined with MF59 adjuvant emulsion in elderly subjects, immunized for three consecutive influenza seasons.

A clinical trial to evaluate the safety and tolerability of a new influenza adjuvanted vaccine (FLUAD, Chiron Vaccines), compared with a conventional non adjuvanted influenza vaccine, was conducted in elderly ambulatory patients. Subjects were vaccinated with one dose of either vaccine each year for three consecutive years; 92 subjects received the first immunization, 74 subjects received the second and 67 subjects received the third. The primary objective of this study was to evaluate the safety of repetitive injections of the adjuvanted vaccine in elderly subjects. There were no reports of any vaccine-related serious adverse event or of safety concerns related to study vaccines after the first, second or third immunization. The adjuvanted vaccine induced more local reactions than the conventional vaccine; however, the reactions were normally mild and limited to the first 2-3 days after immunization. No statistically significant difference between groups in systemic postimmunization reactions was reported except for a mild, transient malaise after the first immunization. Compared with the first immunization, no increase in postimmunization reactions was seen after the second and third immunizations. Despite the small sample size of the trial, which was not powered to test immunogenicity differences, the antibody response was tested and resulted higher in the adjuvanted vaccine recipients, not only against the current seasons vaccine strains, but also against heterologous vaccine strains.

Cross-protection by MF59-adjuvanted influenza vaccine: neutralizing and haemagglutination-inhibiting antibody activity against A(H3N2) drifted influenza viruses.

Adjuvants enhance antibody response against vaccination. We compared the ability of MF59-adjuvanted and non-adjuvanted subunit influenza vaccines, containing A/Wyoming/3/03(H3N2), to confer cross-protection against four consecutive drifted strains in the elderly. Neutralizing and haemagglutination-inhibiting antibody were measured. MF59-adjuvanted vaccine induced a stronger booster response against A/Panama/2007/99(H3N2) than non-adjuvanted vaccine. A/Panama/2007/99(H3N2) circulated widely during the previous 5 years and was included in vaccines over four consecutive seasons. Broader serological protection against drifted strains that circulated 1 and 2 years after vaccination with A/Wyoming/3/03(H3N2) was observed with MF59-adjuvanted vaccine. Thus, MF59-adjuvanted vaccine confers greater immunogenicity than non-adjuvanted vaccines in vulnerable populations.

Burden of influenza in healthy children and their households

Objective: A prospective, multicentre study was conducted to evaluate the burden of laboratory confirmed influenza in healthy children and their household contacts. Methods: The patients were enrolled in four emergency departments (EDs) and by five primary care paediatricians (PCPs) in different Italian municipalities 2 days a week between November 1, 2001 and April 30, 2002. The study involved 3771 children less than 14 years of age with no chronic medical conditions who presented with a respiratory tract infection in EDs or PCP outpatient clinics during the study period. Nasopharyngeal swabs were collected for the isolation of influenza viruses and RNA detection. Information was also collected concerning respiratory illnesses and related morbidities among the study children and their household contacts. Results: Influenza virus was demonstrated in 352 cases (9.3%). In comparison with the influenza negative children, those who were influenza positive had an older mean age, were more often attending day care centres or schools, more frequently experienced fever and croup, received more antipyretics, and had a longer duration of fever and school absence. Furthermore, their parents and siblings had more respiratory illnesses, received more antipyretics and antibiotics, needed more medical visits, missed more work or school days, and needed help at home to care for the ill children for a longer period of time. Conclusions: Influenza has a significant clinical and socioeconomic impact on healthy children and their families. Prevention strategies should also focus on healthy children regardless of their age because of their role in disease transmission.

Novel Approach To Reduce the Hepatitis C Virus (HCV) Window Period: Clinical Evaluation of a New Enzyme-Linked Immunosorbent Assay for HCV Core Antigen

ABSTRACT The window period in hepatitis C virus (HCV) infection is still a major problem in ensuring blood safety. HCV RNA detection by nucleic acid amplification technology-based tests has contributed to reduce the infectivity of blood products, but it is expensive, time-consuming and affected by a high prevalence of false-positive results. The aim of this study was to assess the performance of a newly developed enzyme immunoassay for the detection of HCV core antigen and its suitability for use in the screening of blood units in order to identify infecting samples that do not contain specific antibodies. For evaluation of laboratory performance, different samples were selected: to evaluate specificity, we tested 2,586 sera from blood donors, 500 general population samples, and 58 “difficult sera”. All samples were tested by two screening assays, and results were negative. To estimate clinical sensitivity, 103 HCV RNA-positive, anti-HCV-negative samples, 6 natural seroconversion panels, and 9 commercial seroconversion panels were tested. Intra- and interassay precision were determined on two HCV-RNA-positive, anti-HCV-negative sera. Seventeen (0.66%) blood donor samples, 2 (0.4%) general population samples, and 2 (3.44%) difficult sera were initially reactive; 3 sera were positive on repetition. These 21 samples tested by reverse transcription-PCR were negative. The clinical sensitivity calculated with seroconversion panels and seroconverted patient samples was very similar to PCR sensitivity: 95% of PCR-positive, antibody-negative samples contained detectable HCV antigen. Data on intra- and interassay precision showed dispersion indices with values of less than 10%. In conclusion, the HCV antigen assay showed high sensitivity and specificity and could become a useful means of improving the safety of blood and blood products.

Effect of a rapid influenza diagnosis

Managing children with influenza-like illness is associated with costly and painful interventions because, in order to distinguish viral from bacterial infections, diagnostic tests (including routine blood examinations and chest radiographs) are frequently performed,1,2 and the empirical use of antimicrobial agents is common.3 Various rapid diagnostic techniques for the detection of influenza viruses have been developed, but few data are available on their impact on child care.2,4,5 The aim of this study was to assess the effect of a rapid diagnosis of influenza infection on the management of children with influenza-like illness in an emergency department. All patients seen for influenza-like illness from 6 January to 27 February 2002, at the paediatric emergency department of the University of Milan, Italy, were enrolled and blindly randomly assigned in a 1:1 ratio to undergo a rapid test for the detection of influenza viruses or no rapid test. Influenza-like illness was defined as an axillary temperature of ⩾37.8°C and at least one symptom of acute upper or lower respiratory tract disease.6 The patients who underwent the test had their throats swabbed after vigorously rubbing both tonsillar surfaces and the posterior pharynx; the swab was then immediately submitted to the Quickvue influenza test (Quidel, Milan, Italy) for the rapid detection of influenza A and B viruses. The test, which has an overall sensitivity of 74–95% and an overall specificity of 76–98%,5,7,8 was performed by a postgraduate student in accordance with the manufacturer’s recommendations. The results were available after 10 …

The European Sero-Epidemiology Network: standardizing the enzyme immunoassay results for measles, mumps and rubella.

The ESEN (European Sero-Epidemiology Network) project was established to harmonize the seroepidemiology of five vaccine preventable infections including measles, mumps and rubella in eight European countries. This involved achieving comparability both in the assay results from testing in different centres and also sampling methodology. Standardization of enzyme immunoassay results was achieved through the development of common panels of sera by designated reference centres. The panels were tested at the reference laboratory and then distributed to each participating laboratory for testing using their routine methods. Standardization equations were calculated by regressing the quantitative results against those of the reference laboratory. Our study found large differences in unitage between participants, despite all using an EIA method standardized against an international or local standard. Moreover, our methodology adjusted for this difference. These standardization equations will be used to convert the results of main serosurvey testing into the reference country unitage to ensure inter-country comparability.

Universal childhood immunisation against Streptococcus pneumoniae: The five-year experience of Liguria Region, Italy

Liguria was the first Italian Administrative Region, since 2003, to actively recommend free-of-charge immunisation, of all infants, with heptavalent Pneumococcal Conjugate Vaccine (PCV-7), within a research pilot-project. Vaccination coverage among infants rapidly increased from 42.8% in 2003 to 83.3% in 2004, progressively reaching levels of 93.4% in 2007. Two scientific projects have been carried out, aimed: (i) to assess the immunogenicity of PCV-7 and of a hexavalent vaccine Diphtheria-Tetanus-Trivalent Acellular Pertussis-Hepatitis B-Inactivated Polio Virus-Haemophilus influenzae type B (DTaP-HBV-IPV-Hib) when co-administered to healthy infants at 3, 5 and 11-12 months of age (routine schedule), and (ii) to evaluate the effect of the immunisation campaign in preventing pneumococcal-associated hospitalisations. Results in 151 infants showed the high immunogenicity of the vaccines, seroprotection rates, measured 1 month after the third dose, ranging between 97.3% (serotype 6 B) and 100% (serotypes 4 and 9 V) for PCV-7 and between 99.3% and 100% against common antigens of hexavalent vaccine. Monitoring nearly 70,000 children, aged 0-24 months, during the period 2000-2007, and comparing hospitalisation rates occurred in subjects belonging to birth cohorts before and after the introduction of widespread immunisation, a significant decline for all-cause and pneumococcal pneumonia and for acute otitis media was observed, with preventive fractions of 15.2%, 70.5% and 36.4%, respectively.

The seroepidemiology of varicella in Italy.

We conducted a seroepidemiological study to evaluate the potential impact of mass varicella vaccination on the transmission of varicella-zoster virus (VZV) in Italy, where vaccination is not mandatory. We tested 3179 serum samples, collected from September 1996 to October 1997, for specific anti-VZV antibodies using a commercially available ELISA. The results confirmed that varicella typically involves children (82.1% seroprevalence among 10- to 14-year-olds) and that the mean age of acquiring the infection seems to be increasing. The results also revealed that southern Italy, compared to the rest of the country, has a greater circulation of VZV and an earlier age of acquisition. The potential impact of mass vaccination among 12- to 18-month-old children on the epidemiological trend of the infection must be carefully considered, in that failure to reach high levels of coverage could lead to an increase in the mean age of acquisition, which is already occurring in Italy.

The seroepidemiology of rubella in western Europe

Most of the countries in western Europe have now implemented mass infant rubella immunization programmes, instead of or in addition to selective vaccination in order to achieve the elimination of congenital rubella syndrome. The European countries Denmark, England and Wales, Finland, France, Germany, Italy and the Netherlands undertook large, national serological surveys collecting several thousand serum specimens during 1994-8. Antibodies against rubella virus were detected by a variety of enzyme immuno-assays. Comparability of the assay results was achieved by a standardized methodology. The age- and sex-stratified serological results were related to the schedules, coverage of rubella vaccination and the incidence in these countries. The results show widely differing levels of immunity to rubella both in the general population and in the specific age groups of males and females. A low rate (< 5%) of susceptibles in childhood and adolescents of both sexes was obtained only in Finland and the Netherlands. Countries such as Italy with only moderate coverage for the infant immunization programme currently have both high susceptibility levels in the general population and in the at-risk population. The likelihood is of continued epidemics of rubella with cases of congenital rubella syndrome. The continued implementation of selective vaccination will help to offset the impact of this ongoing transmission and to protect women on reaching childbearing age.

The seroepidemiology of measles in Western Europe

The European Regional Office of WHO has targeted measles for elimination from the region in 2007. Large national, age and sex stratified serological surveys of measles antibody were conducted in seven Western European countries from 1994-8 as part of the European Seroepidemiology Network. Three patterns were observed in the country-specific measles seroprofiles, ranging from (very) low susceptibility (four countries) to high susceptibility (one country). Susceptibility levels amongst 2-4-year-olds ranged from 2.9 to 29.8%, in 5-9-year-olds from 2.5 to 25% and 10-19-year-olds from 2.1% to 13.9%. A countrys susceptibility profile was highly associated with vaccine coverage for the first dose. First dose coverage ranged from 91 to 97.5% for low susceptibility countries, 75 to 85% for intermediate susceptibility countries and 55% for the high susceptibility country. Only the high susceptibility country still reports epidemic measles. In low susceptibility countries, which have achieved or are very close to measles elimination, the priority will be to maintain high MMR vaccine coverage in all geopolitical units for both vaccine doses. In moderate susceptibility countries there is still some endemic transmission, but also risk of outbreaks as pools of susceptibles accumulate. In the high susceptibility country the priority will be to increase infant vaccine coverage and reduce regional variation in coverage levels.