Seniors’ immune systems weaken as they get older, causing some illnesses that they were immune from when they were younger to now pose a threat. The University of College London wanted to know why this happens, so they did a study to find out. The study shows a new way to make vaccines more effective.
A New Way to Make Vaccines More Effective
The study found that inflammation is the root cause of why vaccines are not as helpful in older people. Doing a test with 175 participants (78 were over 65 years old and the rest were under 40), they injected a fake version of varicella zoster virus (VZV), which causes chicken pox.
Once you have the chicken pox, you are immune to it, but sometimes it surfaces in older adults as shingles. This means that the T cell immune responses weren’t strong enough to fight the virus as they got older. All the participants had the chicken pox, so in theory they should be immune.
Researchers noticed the older subjects showed a weaker response, meaning there was less T cell activation, and less reddening and swelling of the injection site. As a control, they also injected a harmless saline solution in the other arm of each participant. With that injection, many of the people who had the weakest response to the VZV, had a strong inflammation response to the saline. This suggests that too much inflammation was stopping the VZV’s immunity.
Doing a Followup Test
Researchers did a follow up test with 18 of the over 65-year-old participants. They took a drug called Losmapimod, which reduces inflammation responses. The drug was designed for long term use, but with this test, participants only took it for 4 days before being injected with the VZV again. Losmapimod successfully increased the immune responses to the VZV.
“A short-term blockade of the inflammation response opened up a window of opportunity for the immune system to respond effectively,” explained the study’s first author, Dr Milica Vukmanovic-Stejic (UCL Infection & Immunity).
What’s Next
The researchers are currently planning a follow-up study which will test whether a flu vaccine is more effective for the elderly when combined with brief use of Losmapimod. The researchers know that vaccine effectiveness declines as we age, so they are hoping this new way of giving vaccines can make them more helpful.
Read more about the study here.