Cost-Effectiveness of Vaccination of Older Adults with an MF59®-Adjuvanted Quadrivalent Influenza Vaccine Compared to Standard-Dose and High-Dose Vaccines in Denmark, Norway, and Sweden.

Individuals aged 65 years and above are at increased risk of complications and death from influenza compared with any other age group. Enhanced vaccines, as the MF59®-adjuvanted quadrivalent influenza vaccine (aQIV) and the high-dose quadrivalent influenza vaccine (HD-QIV), provide increased protection for older adults in comparison to the traditional standard-dose quadrivalent influenza vaccines (SD-QIV). This study aimed to assess the cost-effectiveness of aQIV compared to SD-QIV and HD-QIV in Denmark, Norway, and Sweden for adults aged ≥65 years. A static decision tree model was used to evaluate costs and outcomes of different vaccination strategies from healthcare payer and societal perspectives. This model projects that compared to SD-QIV, vaccination with aQIV could prevent a combined total of 18,772 symptomatic influenza infections, 925 hospitalizations, and 161 deaths in one influenza season across the three countries. From a healthcare payer perspective, the incremental costs per quality adjusted life year (QALY) gained with aQIV versus SD-QIV were EUR 10,170/QALY in Denmark, EUR 12,515/QALY in Norway, and EUR 9894/QALY in Sweden. The aQIV was cost saving compared with HD-QIV. This study found that introducing aQIV to the entire population aged ≥65 years may contribute to reducing the disease and economic burden associated with influenza in these countries.

The Performances of Three Commercially Available Assays for the Detection of SARS-CoV-2 Antibodies at Different Time Points Following SARS-CoV-2 Infection.

The aim of this study was to evaluate the performances of three commercially available antibody assays for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies at different time points following SARS-CoV-2 infection. Sera from 536 cases, including 207 SARS-CoV-2 PCR positive, were tested for SARS-CoV-2 antibodies with the Wantai receptor binding domain (RBD) total antibody assay, Liaison S1/S2 IgG assay and Alinity i nucleocapsid IgG assay and compared to a two-step reference ELISA (SARS-CoV-2 RBD IgG and SARS-CoV-2 spike IgG). Diagnostic sensitivity, specificity, predictive values and Cohen's kappa were calculated for the commercial assays. The assay's sensitivities varied greatly, from 68.7% to 95.3%, but the specificities remained high (96.9-99.1%). The three tests showed good performances in sera sampled 31 to 60 days after PCR positivity compared to the reference ELISA. The total antibody test performed better than the IgG tests the first 30 days and the nucleocapsid IgG test showed reduced sensitivity two months or more after PCR positivity. Hence, the test performances at different time points should be taken into consideration in clinical practice and epidemiological studies. Spike or RBD IgG tests are preferable in sera sampled more than two months following SARS-CoV-2 infection.

Long COVID in a prospective cohort of home-isolated patients.

Long-term complications after coronavirus disease 2019 (COVID-19) are common in hospitalized patients, but the spectrum of symptoms in milder cases needs further investigation. We conducted a long-term follow-up in a prospective cohort study of 312 patients-247 home-isolated and 65 hospitalized-comprising 82% of total cases in Bergen during the first pandemic wave in Norway. At 6 months, 61% (189/312) of all patients had persistent symptoms, which were independently associated with severity of initial illness, increased convalescent antibody titers and pre-existing chronic lung disease. We found that 52% (32/61) of home-isolated young adults, aged 16-30 years, had symptoms at 6 months, including loss of taste and/or smell (28%, 17/61), fatigue (21%, 13/61), dyspnea (13%, 8/61), impaired concentration (13%, 8/61) and memory problems (11%, 7/61). Our findings that young, home-isolated adults with mild COVID-19 are at risk of long-lasting dyspnea and cognitive symptoms highlight the importance of infection control measures, such as vaccination.

COVID-19 and venous thromboembolism - prophylaxis and treatment. / Covid-19 og venøs tromboembolisme ­ profylakse og behandling.

As the pandemic has been unfolding, reports have emerged of a relatively high incidence of coagulopathy and thromboembolic events in connection with COVID-19 infections. Raised awareness surrounding this issue, and appropriate antithrombotic prophylaxis and treatment, are therefore important for this group of patients.

Influenza A haemagglutinin specific IgG responses in children and adults after seasonal trivalent live attenuated influenza vaccination.

Influenza is a major respiratory pathogen and vaccination is the main method of prophylaxis. In 2012, the trivalent live attenuated influenza vaccine (LAIV3) was licensed in Europe for use in children. Vaccine-induced antibodies directed against the main viral surface glycoprotein, haemagglutinin (HA), play an important role in virus neutralization through different mechanism. The objective of this study was to dissect the HA specific antibody responses induced after LAIV3 immunization to the influenza A viruses in children and adults. Plasma was collected from 20 children and 20 adults pre- and post-LAIV3 vaccination (up to ayear) and analysed by the haemagglutination inhibition (HI) and ELISA assays. We found that LAIV3 boosted the HA specific IgG response against the head and the full-length of H3N2 in children, but not adults. Adults had higher levels of pre-existing stalk antibodies (towards H3N2 and H1N1), but these were not boosted by LAIV3. Importantly, we observed a trend in boosting of H1N1 HA stalk specific antibodies in children after LAIV3. Whereas, heterosubtypic H5 and H7 full-length HA specific antibodies were not boosted in either children or adults. In conclusion, LAIV3 elicited H3-head and low levels of H1 stalk specific antibody responses in children, supporting the prophylactic use of LAIV in children.

Live Attenuated Influenza Vaccine in Children Induces B-Cell Responses in Tonsils.

BACKGROUND: Tonsils play a key role in eliciting immune responses against respiratory pathogens. Little is known about how tonsils contribute to the local immune response after intranasal vaccination. Here, we uniquely report the mucosal humoral responses in tonsils and saliva after intranasal live attenuated influenza vaccine (LAIV) vaccination in children. METHODS: Blood, saliva, and tonsils samples were collected from 39 children before and after LAIV vaccination and from 16 age-matched, nonvaccinated controls. Serum antibody responses were determined by a hemagglutination inhibition (HI) assay. The salivary immunoglobulin A (IgA) level was measured by an enzyme-linked immunosorbent assay. Antibody-secreting cell (ASC) and memory B-cell (MBC) responses were enumerated in tonsils and blood. RESULTS: Significant increases were observed in levels of serum antibodies and salivary IgA to influenza A(H3N2) and influenza B virus strains as early as 14 days after vaccination but not to influenza A(H1N1). Influenza virus-specific salivary IgA levels correlated with serum HI responses, making this a new possible indicator of vaccine immunogenicity in children. LAIV augmented influenza virus-specific B-cell responses in tonsils and blood. Tonsillar MBC responses correlated with systemic MBC and serological responses. Naive children showed significant increases in MBC counts after LAIV vaccination. CONCLUSIONS: This is the first study to demonstrate that LAIV elicits humoral B-cell responses in tonsils of young children. Furthermore, salivary IgA analysis represents an easy method for measuring immunogenicity after vaccination.