Measles in Albania: Humoral Immune Response to Measles among the Vaccinated Albanian Population

Measles outbreaks occurred predominantly among unvaccinated individuals; therefore, achieving high vaccination coverage is the primary goal for disease prevention. Epidemiological studies have shown that the level of neutralizing antibodies at the time of exposure to wild-type (WT) virus during a measles outbreak is a good indicator of protection against infection, with higher antibody titers being required to prevent infection rather than merely prevent disease (Yeung et al., 2016).

Consequently, from a public health perspective, it is essential to understand the level of measles seroprevalence in the population. Given that the Albanian population has received different measles vaccine formulations (monovalent, bivalent, and trivalent) as well as different immunization schedules (Table 2), it is essential to determine how these factors influence immune memory over the years.

Individuals vaccinated with different measles vaccine formulations and according to different immunization schedules may exhibit **different levels of antibodies against measles virus (MV).**However, in 1971, measles vaccination became mandatory as a single-dose regimen, accompanied by a mass vaccination campaign targeting Albanians born between 1956 and 1970.The introduction of a booster dose in early 2001, as part of the National Immunization Programme, may have resulted in higher antibody titers compared with individuals who received only a single dose.The most recent measles outbreaks were recorded in Elbasan in 2006 and Shkodër in 2007. It is possible that individuals born in these cities may have higher antibody titers compared with residents of Tirana, where no outbreaks were reported.

To address these questions, we aim to perform ELISA and plaque reduction neutralization tests (PRNT) at the NATO Laboratory of Cellular and Molecular Virology, Catholic University “Our Lady of Good Counsel”, Tirana, to determine antibody titers against measles virus (MV) in serum samples from healthy Albanian children, adolescents, and adults born in Tirana, Elbasan, and Shkodër.

In particular, MV (Edmonston strain, VR-24) will be provided by BEI Resources (NIAID, NIH, USA).

Project objectives

1. To evaluate the immunogenicity of measles vaccines used in Albania over the years (10–80 years age group).

2. To measure and compare antibody levels according to age groups and city of birth, as well as to assess the immunogenicity of measles vaccines used in Albania over time.

3. To determine whether the presence of antibodies in serum is the result of natural infection or vaccination.

4. To compare measles antibody levels among unvaccinated individuals, those vaccinated with one dose, and those vaccinated with two doses.

5. To compare antibody levels among individuals vaccinated with monovalent, bivalent (MR), and trivalent (MMR) vaccines.

6. To analyze the association between sociodemographic factors (age, gender, geographic area) and antibody levels in order to identify populations requiring targeted interventions.

7. To promote risk communication strategies for vaccine acceptance and to identify factors influencing suboptimal vaccine uptake.

8. To address logistical barriers and improve access to vaccines for populations in hard-to-reach (low-access) areas.

9. To increase clinical awareness among healthcare professionals regarding the importance of verifying vaccination status and maintaining immunity.

10. To disseminate scientific results with the aim of increasing their impact on public health policies and the development of scientific research.