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The validation of a bioanalytical method allows us to determine its validity for a designated purpose and to guarantee the reliability of its analytical results. The virus neutralization assay has proved to be suitable for the detection and quantification of specific serum‐neutralizing antibodies against respiratory syncytial virus subtypes A and B. Respiratory syncytial virus is a negative‐sense RNA virus and is responsible for the majority of acute lower respiratory tract infections in infants and older adults worldwide. Owing to its widespread infection, the WHO considers it a target for the development of preventive vaccines. Despite the high impact of its infections, however, only one vaccine has been recently approved. The aim of this paper is to provide a detailed validation process for the microneutralization assay and to demonstrate that this method can effectively support the efficacy assessment of candidate vaccines and the definition of correlates of protection. [ABSTRACT FROM AUTHOR]

Background: Vaccine effectiveness relies on various serological tests, whose aim is the measurement of antibody titer in serum samples collected during clinical trials before and after vaccination. Among the serological assays required by the regulatory authorities to grant influenza vaccine release there are: Hemagglutination inhibition (HAI), microneutralization (MN), and Single Radial Hemolysis (SRH). Although antibodies are regarded to be relatively stable, limited evidences on the effect of multiple freeze–thaw cycles on the stability of antibodies in frozen serum samples are available so far. In view of this, the present paper aimed to evaluate the impact of multiple freeze–thaw cycles on influenza antibody stability, performing HAI, MN and SRH assays. Methods: Ten serum samples were divided into 14 aliquots each, stored at −20 °C and taken through a total of 14 freeze–thaw cycles to assess influenza antibody stability. Each assay measurement was carried out following internal procedures based on World Health Organization (WHO) guidelines. Results: No statistically significant effect of 14 freeze–thaw cycles on antibody stability, measured through three different assays, was observed. Conclusions: Collectively, these data demonstrated that specific influenza antibody present in serum samples are stable up to 14 freeze–thaw cycles. [ABSTRACT FROM AUTHOR]