Restart the Clinical Vaccination Study

VITAL’s Work Package 2 has reinitiated the clinical vaccination study on the immune responses to influenza and pneumococcal conjugate vaccines in older adults compared to middle-aged adults and adults. Due to the COVID-19 pandemic and the restrictions that came with controlling it in spring 2020, the study was on hold after the inclusion of 40 individuals. The team was able to do the follow-up of these individuals, but other vaccinations were postponed. On July 13th  the team was able to re-start giving the PCV13 vaccinations again, and hope to finish the remaining follow-up of 286 individuals in the next few months.

Adults of 65 years and older are more vulnerable to infections due to a decline in immune responses with ageing (immune-senescence). Due to the increase in the percentage of older adults, the number of people with severe infectious disease-related health problems is also increasing. Vaccines are one of the most effective means to protect against different infections. However, the responses to vaccines in elderly may vary considerably. This study aims to compare the immune responses induced by two vaccines and helps to understand underlying mechanisms of non-responsiveness in different age groups.

All participants of the study have received the seasonal influenza vaccine (quadrivalent inactivated influenza vaccine) during autumn 2019 and were followed up for a month post-vaccination. A pneumococcal vaccination (13-valent pneumococcal conjugate vaccine, PCV13) was planned to start in March 2020 in the same individuals. The main objective of this trial is getting a better insight in the influence of age and age-related changes by internal and external factors on vaccine-induced immune responses and gain knowledge on the trajectory of immune decline in older adults, pre-elderly (middle-aged) adults in comparison to adults. The ultimate goal is to formulate evidence-based strategies to improve immunity to vaccines in the ageing population.

Knowledge on which parameters of the immune system or external factors contribute to decreased immune responsiveness to vaccines can provide leads to improve vaccine responsiveness in general. In addition, this information can be used to predict effective or non-effective immune responses in specific subsets of individuals. Eventually this information may help to design optimal future vaccination strategies.

About Work package 2

Work package 2 aims to obtain a better insight into changes in the immune response with age, to evaluate the impact of (external) factors on vaccine performance in the aging adults and to formulate evidence-based rationale strategies for improving immunity to infections by vaccination in the ageing population such as vaccinating pre-aging adults. Read more about Work Package 2.