Current evidence suggests that immunity after the disease is life-long, whereas the response after two doses of measles-containing vaccine declines within 10–15 years.
Although the immune responses induced by the vaccine are qualitatively similar to those induced by infection, antibody levels are lower after vaccination.
Vaccination at a young age enhances the quality and quantity of the antibody response but has a minor effect on T cell responses.
[O]ver time, virus-specific antibodies and vaccine-induced CD4 + T cells decrease, accounting for the secondary vaccine failure rate of 5% 10–15 years after immunization.
Our study… provides further evidence that natural immunity is more long-lasting than vaccine immunity. Additional support for this conclusion comes from the significantly higher baseline GMT [geometric mean titer] in the naturally immunized group…
[A]mong subjects who received two doses of measles vaccine, the neutralizing antibody titer tended to decline over time, on contrary of natural immunized subjects.
A key to the interpretation of our data is to define the role of circulating antibodies and memory B cells in protecting against wild virus.
Protection correlates better with the quality and quantity of the induced neutralizing antibodies, but the development of immunity against the disease is probably largely determined by T cells.
Studies on macaques have shown that neutralizing antibodies provide protection from the disease (rash) but not necessarily from infection…
While further research is needed, our study clearly showed that natural immunity is both more robust and longer-lasting than vaccine immunity.
The results of this study highlight the risk of a loss of antibodies over time. Thus, from now until the next 10–20 years, the vaccinated population can be expected to lose circulating antibodies such that their susceptibility to measles may increase.
Moreover, since it is highly unlikely that measles will be eliminated in the immediate future, a part of individuals vaccinated several years ago will soon lose their circulating antibodies, such that outbreaks of the disease in the coming years can be expected.