Immunity against measles in populations of women and infants in Poland
Introduction
During the 1997–1998 measles epidemic in Poland cases occurred at all ages less than 30 years but showed two distinct peaks: unvaccinated infants under 1 year of age and once vaccinated adolescents and young adults aged 16–21 years. Infections of young children may often be accompanied by significant complications [1], [2], and an increased risk of developing subacute sclerosing panencephalitis later in life [3], [4].
During the last weeks of pregnancy, the foetus receives measles antibodies from his mother through placenta. The antibody level in infant is thus proportional to, but higher than in the mother’s serum [5]. Natural infection with measles virus induces higher antibody levels than vaccination [6], so vaccinated mothers transfer less antibodies to their infants than mothers who had measles infection in their childhood [7], [8], [9], [10], [11], [12].
The immunogenicity of measles vaccine in infancy is dependent on the rate of decay of maternal antibody since these antibodies interfere with vaccine-induced seroconversion. If measles vaccine is administrated when maternal antibodies are still present, the immune response of infant may be inhibited or weaker then that of infant with no maternal antibodies.
The titer of these passively acquired antibodies gradually decreases after birth [7], [13]. Early loss of passive measles antibody occurs in infants whose mothers received measles vaccine [10], [11], [12], [14], so infants from vaccinated mothers are more susceptible to measles [15].
Development of protective immunity after vaccination depends on several conditions. One of them is development of specific cellular immunity after measles vaccination and the relationship between humoral and cell-mediated responses in conferring protective immunity [16]. It was shown that maternal measles antibodies inhibited antibody but not T cell responses in mice [17].
Measles vaccination in young infants is less effective than in older infants also in the absence of maternal antibodies [18], [19], [20]. The more immature immune system of young infants responds less effectively to measles vaccination. The adjusted vaccination schedules may also influence on the efficacy of measles vaccination [21], [22]. Decreasing the age of second measles vaccination is more effective than decreasing the age of the first measles vaccination.
Routine vaccination against measles for children aged 13–15 months was introduced in Poland in 1975. A part of children who were born in 1969–1974 (about 20%) have also been vaccinated. A second dose of measles vaccine was added to the vaccination schedule of 9-year-old children in 1991 and was brought forward to 7 years olds in 1994.
Primary measles vaccination after 12 months of age is based on epidemiological data gathered in the 1960s when most mothers had a natural measles.
Nowadays, most mothers have received measles vaccine. In well-vaccinated maternal population the susceptibility to measles in younger infants is higher. Protective levels of maternal antibodies in newborns have waned several months before the first vaccination is scheduled [23], so measles vaccination before the currently recommended age may be more effective. Therefore, measles-specific antibody titres were determined for vaccinated and unvaccinated women as well as for infants aged 6–14 months, whose mothers were born before 1969 and likely had a natural measles and those whose mothers were born after 1976 and likely were vaccinated.
Section snippets
Attack rates
Clinically diagnosed measles cases were reported to field sanitary epidemiological stations. The data for each voivodeship were collected by the voivodeship sanitary epidemiological stations according to age, sex, region and vaccination status and reported twice a month to the Epidemiology Department in the National Institute of Hygiene [24]. The attack rate for each age group was calculated as: AR=(NC/NR)×100,000, where NC denotes the number of cases, and NR the population in risk of measles
Results
For evaluation of impact of measles vaccination on the change of measles antibodies level in population, serum samples from teenage girls and young women were compared. There were extremely significant differences (P<0.001) between geometric mean antibody titres in groups of vaccinated girls and young women (aged 10–20 years), and unvaccinated women at age over 20 years (Fig. 1). Analysis of distribution of measles virus antibody titres by year of birth showed considerable age dependence (Fig. 2
Discussion
Nowadays, many infants in Poland receive less antibody at birth from their mothers and became both susceptible to measles and responsive to the vaccine at an earlier age in comparison with infants living in the prevaccination era.
In Poland, routine vaccination against measles for children aged 13–15 months was introduced in 1975, but a small proportion (about 20%) of older children born between 1969 and 1974 was also vaccinated. Since 1980 national coverage for the first dose of measles vaccine
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Cited by (28)
Measles susceptibility in maternal-infant dyads—Bamako, Mali
2022, VaccineCitation Excerpt :Specifically, infection with wild-type measles virus induces higher measles titers compared with vaccination. Therefore, infants born to mothers who had been infected with wild-type measles virus have higher levels of maternally derived measles antibodies at birth and their protection is expected to last longer than infants born to vaccinated mothers [11–17]. The duration of acquired maternal protection is particularly relevant in AFR, where the first dose of measles containing vaccine (MCV1) in the routine immunization (RI) program is given to infants at nine months [1]; age at MCV1 administration is a program decision based on the level of measles transmission within the region.
A 16-year review of seroprevalence studies on measles and rubella
2016, VaccineCitation Excerpt :This approach was particularly useful when comparing seroprevalence of individuals in age groups that did not undergo vaccination programmes with those that did. The age groups that were not vaccinated generally had lower seroprevalence but a higher GMT [3,16]. The immune levels in infants who acquired protection from maternal antibodies declined rapidly over time.
Duration of maternally derived antibody against measles: A seroepidemiological study of infants aged under 8 months in Qinghai, China
2012, VaccineCitation Excerpt :This result is consistent with previous study [26]. We did not find a significant difference in average maternal antibody levels between infants born to mothers who reported that they had natural measles infection and those born to mothers who reported that they had vaccination against measles, although several studies have suggested that measles antibody titres induced by vaccination are lower [27–29] and decline earlier in maternal derived antibodies [10,11,27,30–34] than those induced by natural infection. The possible explanation is that mother's history of vaccination and measles natural infection was obtained only through her own recall, without the confirmation of individual health records, moreover, the majority of mothers could not remember clearly whether they had been vaccinated against measles or had natural measles infection during childhood, thus subject to recall bias.
Passive transmission and persistence of naturally acquired or vaccine-induced maternal antibodies against measles in newborns
2007, VaccineCitation Excerpt :Maternal age was used as a proxy for the vaccination status of the mother [35]. Janaszek and Slusarczyk [36] and Szenborn et al. [37] describe the situation in Poland in 2003 with a faster decay of maternal measles antibodies in children from vaccinated mothers. Earlier vaccination at 9 months was suggested, with administration of a second dose of MMR at 15 months.