Safety and efficacy of early vaccination with live attenuated measles vaccine for hematopoietic stem cell transplant recipients and solid organ transplant recipients

Background and objectiveVaccination with the live attenuated measles vaccine is currently recommended two years after hematopoietic stem cell transplantation (HSCT) and generally contraindicated after solid organ transplantation (SOT) due to safety concerns.However, in the last few years new data on the administration of the measles vaccine to HSCT recipients less two years post-transplantation and to SOT recipients have become available.This new data may change current guidelines and practices. The objective of this review is to provide an overview of the current data on the safety and efficacy of early measles vaccination for HSCT- and SOT recipients.MethodPubMed and EMBASE were searched from the earliest date available through October 2019 to identify all research that reported on the safety and efficacy of measles vaccination after SOT or less than two years after HSCT.ResultsA total of ten studies was included in this review. In the six studies that evaluated the efficacy of measles vaccination after SOT, seroconversion rates ranged from 41 to 100% after one dose and 73 to 100% after two doses. In the four studies that evaluated the efficacy of measles vaccination less than two years after HSCT, seroconversion rates ranged from 33 to 100% after one dose and 100% after two doses. In all studies, the administration of the measles vaccine after transplantation was considered to be safe. There were no cases of infection with the attenuated vaccine strain, and there were no adverse events related to the vaccination.ConclusionData on the administration of the measles vaccine after SOT and less than two years after HSCT is scarce. However, the current data available suggest that it is efficacious and well tolerable. Therefore, early measles vaccination could be considered in selected groups of SOT- and HSCT recipients during increased measles transmission or an outbreak setting.     

Vaccination of allogeneic haematopoietic stem cell transplant recipients: report from the international consensus conference on clinical practice in chronic GVHD

Patients lose protective immunity to vaccine-preventable diseases after haematopoietic stem cell transplantation (HSCT). Therefore, revaccination of HSCT recipients represents an important strategy for reducing morbidity and mortality associated with these infections. Since there is little consensus on vaccine recommendations and practices for allogeneic HSCT recipients with active chronic graft-versus-host disease (GVHD) the German-Austrian-Swiss-Consensus Conference on Clinical Practice in Chronic GVHD developed an immunization schedule with the aim to provide optimal patient care. The proposed vaccine recommendations include immunization against Haemophilus influenzae type b, pertussis, pneumococci, meningococci, tetanus, diphtheria, hepatitis A and B, measles, mumps and rubella, influenza, poliomyelitis, varicella-zoster virus, human papilloma virus, and tick-borne encephalitis with a particular focus on vaccination of patients with active chronic GVHD.     

Persistence of antibodies in 4-8 year old Austrian children after vaccination with hexavalent DTaP-HBV-IPV/Hib and MMR vaccines

To determine the proficiency of the Austrian childhood vaccination schedule to induce long lasting seroprotection against vaccine preventable diseases a seroepidemiological study in 348 children between four and eight years of age was conducted. Antibodies against diphtheria, tetanus, pertussis, hepatitis B, measles, mumps and rubella antigens were assessed in children, who had been vaccinated with hexavalent DTaP-HBV-IPV/Hib vaccines at three, four, five months and in the second year of life and/or MMR vaccines in the second year of life at least once, but mostly twice.High seroprotection rates (SPRs) were detected for tetanus (96%) and measles (90%). SPRs regarding diphtheria and mumps were 81% and 72%, respectively. Rubella-SPRs were 68% in females and 58% in males. Hepatitis B-antibody levels ≥10 mIU/mL were present in 52%; antibodies against pertussis were detected in 27% of the children. SPRs for measles and rubella depended on the interval since last vaccination; mumps-antibodies were significantly lower after one MMR-vaccination only. Antibodies against diphtheria, tetanus and pertussis depended on the interval since last vaccination while HBs-antibodies did not. The low levels of antibodies 1-7 years after vaccination against pertussis, rubella and mumps after only one vaccination should be considered when recommending new vaccination schedules.     

Inadequate immunity to measles in children vaccinated at an early age: effect of revaccination

This report describes a follow-up serological study of 79 Brazilian children who, because of their young age, had failed to develop protective levels of immunity after vaccination against measles. There was serological evidence that infection with wild virus had occurred at a rate of about 17% per annum. Approximately 1½ years after the initial vaccination, 46% of the uninfected children maintained very low levels of neutralizing antibody, but did not have a measurable haemagglutination-inhibition titre. Revaccination did not elicit an IgM response in most children, but stimulated anti-measles IgG production in all of them. In 36% of the children, the IgG titres fell again within three months to levels that may permit reinfection. If it is assumed that some of the persistent titres can be attributed to wild virus infection, the actual effect of revaccination would have been to immunize no more than 60% of the susceptible group. The results suggest that early administration of measles vaccine may produce a cohort of children with inadequate immunity who cannot be fully immunized by revaccination. The implications of these findings for measles immunization programmes are discussed.     

Seroprevalence and immunization history of selected vaccine preventable diseases in medical students

To evaluate protection against vaccine-preventable diseases in medical students, we obtained data on immunization status and history of diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, rubella, varicella and hepatitis B from students with elective periods in our institution. Further, serum antibodies against measles, mumps, rubella and varicella-zoster virus (VZV) and hepatitis B surface (HBs) antigen were determined on a voluntary basis. For students with incomplete immunization status or lack of protective antibodies, vaccination was offered for free. Success of catch-up immunizations was serologically confirmed 4 weeks later. From May 1999 to April 2003, 170 students were enrolled; their mean age was 26 years with a median of 25 years (range 22-48 years). Immunization records were complete in 148 (87%), incomplete in 11 (6.5%) and missing in 11 (6.5%) students. Only 26% of the cohort had a complete and up-to-date immunization status. Seroprevalence of IgG antibodies against measles, mumps, rubella, VZV and HBs (> or = 10 IU/l) in 149 students were 85, 85, 92, 97 and 90%, respectively. Indications for > or = 1 catch-up immunization were found in 125 (74%) students and were accepted by 97 of them (78%). Sixty two (99%) of 63 immunized students available for follow-up demonstrated an adequate serological response. In conclusion, the great majority of medical students had immunization gaps. Systematic immunization programmes for medical students should be implemented.     

Immunity against measles in populations of women and infants in Poland

During the 1997-1998 measles epidemic in Poland a high attack rate occurred in infants up to 1 year of age (24.6/100,000 in comparison with 5.5/100,000 in total population). Routine vaccination against measles for infants aged 13-15 months was introduced in Poland in 1975, and a second dose added in 1991. The recommended age for measles vaccination was based on information gathered in years when most mothers had a natural measles. Nowadays, many mothers have received measles vaccine. Early loss of passively acquired measles antibody may occur in infants of women who received measles vaccine, because measles vaccine induces lower antibody titres than does natural infection. Therefore, measles-specific antibody titres were determined among vaccinated and unvaccinated women as well as among infants, whose mothers were born after 1976 and likely were vaccinated (Group 1), and those, whose mothers were born before 1969 and likely have had a natural measles (Group 2). All women that were born in prevaccination era had significantly higher geometric mean titre (GMT) of measles antibody than those who were vaccinated (P<0.001). Also infants from Group 2 at every age had higher GMT of measles antibody than those of Group 1. The antibody decay was significantly faster among infants whose mothers acquired immunity by measles vaccination. Because nowadays the majority of women in childbearing age are vaccinated against measles, earlier vaccination in the infants should be considered.     

Diphtheria antitoxin titres six years after basic immunization of adults

Diphtheria antitoxin titres were analysed in 160 adults (median age 59 years, range 34–70), who completed basic vaccination with three doses of 7.5 Lf or 15 Lf of diphtheria toxoid (D) in a previous vaccination trial in 1987, in serum samples drawn 6 years later. The median titre had decreased from 3.2 IU ml⁻¹ in the post vaccination samples to 0.2 IU ml⁻¹ after 6 years in the 15 Lf group and 0.1 IU ml⁻¹ in the 7.5 Lf group. An antitoxin titre of <0.01 IU ml⁻¹, a level usually considered to give no safe protection, was found in 21/73 (29%) individuals, who had received 7.5 Lf and in 12 of 87 (14%), who received 15 Lf diptheria toxoid (P<0.05). In the orginal study, the vaccinees were enrolled as unimmunized based on their own vaccination histories, but many participants had serological evidence of previous immunization. In the subgroup of 48 truly nonimmune participants, i.e. without prevaccination titres and without booster response after the first injection, 46% (32% in the 15 Lf group and 58% in the 7.5 Lf group) had antitoxin levels of <0.01 IU ml⁻¹ 6 years after basic vaccination. Therefore, individuals who have received basic vaccination with three doses of diphtheria toxoid need at least one booster injection 5–10 years later.     

Stop measles in Switzerland – The importance of travel medicine

BackgroundIn line with the worldwide strive to combat measles, the Swiss Federal Office of Public Heath (FOPH) launched a National Strategy for measles elimination 2011–2015. In this study, we highlight the importance of travel medicine consultations to complement measles vaccination programmes based on data from the Travel Clinic of the University of Zurich.MethodWe analysed measles vaccination data from the Zurich Travel Clinic between July 2010 and February 2016 and focused on three groups: (i) all clients who received the measles vaccination, (ii) all clients aged > two years who received the measles vaccination (“catch-up vaccination”), and (iii) all clients aged > two years and born after 1963 (“FOPH recommended catch-up vaccination”).Results107,669 consultations were performed from 2010 to 2016. In 12,470 (11.6%) of these, a measles vaccination was administered; 90.9% measles vaccinations were given during a pre-travel consultation, and 99.4% were administered to individuals aged > two years (“catch-up vaccinations”). An “FOPH recommended catch-up vaccination” was received by 13.6% of all Zurich Travel Clinic clients aged >2 years and born after 1963.ConclusionsIn this study, we highlight the importance of travel medicine consultations to enhance the measles vaccination coverage in the adult Swiss population.     

The humoral immune response of hematopoietic stem cell transplantation recipients to AS03-adjuvanted A/California/7/2009 (H1N1)v-like virus vaccine during the 2009 pandemic

We evaluated the formation of hemagglutination-inhibition (HI) antibodies in response to vaccination of 55 allogeneic and 23 autologous hematopoietic stem cell transplantation (HSCT) recipients with 3.75 μg inactivated influenza A/California/7/2009 (H1N1)v-like virus adjuvanted with AS03, given towards the end of the 2009 influenza pandemic. The 78 HSCT recipients, aged 11-72 (median 50) years, were vaccinated 1-290 (median 27) months post-HSCT. Of the 55 allogeneic HSCT recipients, 50.9% received reduced intensity conditioning, 74.5% had a sibling donor, 67.2% had active graft-versus-host disease and 43.6% were on steroid therapy. At baseline, 14/78 (17.9%) had HI titers ≥1:40. Blood samples of 77 patients were available post-1st vaccination; of these, 34 (44.2%) patients had HI titers ≥1:40. Blood samples of 43 patients were available post-2nd vaccination; of these, 21 (48.8%) had HI titers ≥1:40. There was a significant increase in HI titers ≥1:40 from baseline to both post-1st and 2nd vaccinations (p < 0.001 each), and also from 1st to 2nd vaccination (p = 0.008). In seronegative (HI titers <1:10) patients, whose sera were available before, after one dose, and after 2 doses of vaccine, seroconversion (to ≥1:40) occurred in 4/24 (16.7%) after 1-dose and in a total of 10/24 (41.7%) after 2-dose vaccination (p = 0.031). Logistic regression analysis revealed that ≥1:40 HI titers were significantly associated with higher lymphocyte counts and higher HI baseline titers and, in allogeneic HSCT, with having a sibling donor and higher baseline titers. In conclusion, 2-dose vaccination with AS03-adjuvanted vaccine containing 3.75 μg antigen resulted in a statistically significant, yet limited, serological response. Therefore, additional precautions should be taken during influenza outbreaks.     

IgG antibody prevalence suggests high immunization needs in newcomers to Luxembourg, 2012

Vaccine coverage of the general population in Luxembourg is high, but refugees or asylum seekers may be incompletely vaccinated and susceptible to vaccine-preventable diseases.In order to assess protection rates, serum and oral fluid samples were collected from 406 newcomers aged between 13 and 70 years arriving between May and September 2012. Sera were screened for IgG antibodies against measles, rubella, mumps, hepatitis B, tetanus, diphtheria and pertussis. Oral fluid samples were screened for antibodies against measles, mumps and rubella virus to investigate their suitability for antibody prevalence studies.More than 90% of the participants had IgG antibodies against rubella, 73% against measles and 56% against mumps. Less than 19% had anti-HBs antibodies. Nearly 84% of the participants had an adequate protection against tetanus, 73% against diphtheria and 40% had pertussis antibodies. 93%, 95% and 78% of the measles, rubella and mumps test results obtained with serum and oral fluid were concordant.The majority of the participants lacked antibodies against at least one of the measles/mumps/rubella (58%) and diphtheria/tetanus/pertussis (72%) vaccine components and against hepatitis B virus (82%) and might thus profit from vaccination. Oral fluid is a suitable alternative and non-invasive specimen for measles/rubella antibody prevalence studies.     

Comparative seroepidemiology of pertussis, diphtheria and poliovirus antibodies in Singapore: waning pertussis immunity in a highly immunized population and the need for adolescent booster doses

Background

We assessed the seroepidemiology of pertussis, diphtheria and poliovirus antibodies in a cohort of highly immunized children, together with the burden of these diseases in Singapore.

Methods

Hospital residual sera collected between August 2008 and July 2010 from 1200 children aged 1–17 years were tested for the prevalence of IgG antibodies against Bordetella pertussis, diphtheria toxoid, and all three poliovirus types by enzyme-linked immunosorbent assays.

Results

We found an overall seroprevalence of 99.4% (95% CI 98.8–99.7%) for diphtheria, and 92.3% (95% CI 90.6–93.6%) for poliomyelitis, along with no indigenous cases of these diseases since 1993. However, the seroprevalence for pertussis was 60.8% (95% CI 58.0–63.5%) only. Among the subjects who had completed three doses of pertussis vaccination by the age of 2 years (n = 1092), the pertussis seroprevalence was 85.0% (95% CI 79.7–89.2%) in those who received the last vaccination within a year before the study, and it decreased to 75.0% (95% CI 64.5–83.2%) and 63.1% (95% CI 50.9–73.8%) in those who had the last vaccination 1 year and 2 years before the study, respectively. The seroprevalence remained at about 50% for those whose last pertussis vaccination was administered 4 years and longer before the study.

Conclusions

The high seroprevalence for poliomyelitis and diphtheria confer solid herd immunity to eliminate these diseases in Singapore. In contrast, immunity against pertussis waned considerably over time, and routine boosters should be given to adolescents to ensure sustained immunity against pertussis.     

Are they protected? Immunity to vaccine‐preventable diseases in healthcare workers at an Australian hospital

Objective : Australian guidelines for healthcare worker (HCW) vaccination were updated in 2010, and pre‐employment assessment of new employees has previously been identified as a priority. We determined the vaccination status of a cohort of existing HCWs at a tertiary hospital in Melbourne, Victoria. Methods : Random sampling of HCWs employed prior to 2006 with unknown/incomplete immunisation status was conducted between April and August 2011. Immunity to vaccine‐preventable diseases (VPDs) was determined serologically (hepatitis B, varicella, measles, mumps, rubella) and by questionnaire (diphtheria, tetanus and pertussis), with vaccination by a nurse immuniser. Results : Overall, 95 HCWs were evaluated. Mean age and duration of employment were 47.2 and 12.6 years, respectively. Forty‐seven staff (49%) required vaccination to comply with Australian immunisation guidelines: 18% were non‐immune to hepatitis B, 2% to varicella, 8% to measles, 19% to mumps and 13% to rubella. HCWs without serological hepatitis B immunity were all staff with clinical roles. Total costs were $7,527.34 (mean $222.79/HCW). Conclusions : Immunity to VPDs among existing HCWs was inadequate. About half assessed HCWs were non‐immune to at least one VPD, and non‐immunity to hepatitis B was high. A comprehensive assessment strategy for existing employees is required to enhance vaccination coverage and compliance with national guidelines. Implications : Adequately resourced ‘look‐back’ immunisation assessment programs are required to reduce the risks of VPDs among existing staff and patients. Review of current approaches and national consensus regarding the need for mandatory strategies would assist this process.     

An observational study of antibody responses to a primary or subsequent pertussis booster vaccination in Australian healthcare workers

Adult pertussis vaccination is increasingly recommended to control pertussis in the community. However, there is little data on the duration and kinetics of immunity to pertussis boosters in adults. We compared IgG responses to vaccination with a tetanus, low-dose diphtheria, low-dose acellular pertussis (Tdap) booster at 1 week, 1 month and 1 year post-vaccination in whole-cell (wP)-primed Australian paediatric healthcare workers who had received an adult Tdap booster 5–12 years previously, to those who received their first Tdap booster.Tdap vaccination was well tolerated in both groups. Previously boosted adults had significantly higher pre-vaccination IgG concentrations for all vaccine-antigens, and more were seropositive for pertussis toxin (PT)-specific IgG (≥ 5 IU/mL) (69.5%; 95% confidence interval (CI) 59.5–79.5) than adults in the naïve group (45.2%; 95% CI 32.8-57.5). Tdap vaccination significantly increased IgG responses 1 month post-vaccination in both groups. This increase was more rapid in previously boosted than in naïve adults, with geometric mean fold-increases in PT-IgG at 1 week post vaccination of 3.6 (95% CI 2.9–4.3) and 2.6 (95% CI 2.2–3.2), respectively. Antibody waning between 1 month and 1 year post-vaccination was similar between groups for IgG specific to PT and filamentous haemagglutinin (FHA), but was faster for IgG against pertactin (PRN) in the naïve group (GMC ratio 0.36; 95% CI 0.31–0.42) than the previously boosted group (GMC ratio 0.45; 95% CI 0.39–0.50). At baseline, all but one adult had protective IgG titres against tetanus toxin (TT) (≥ 0.1 IU/mL), and 75.6% in the previously boosted and 61.3% in the naïve group had protective IgG titres against diphtheria toxoid (DT) of ≥ 0.1 IU/mL.This study shows that pertussis immune memory is maintained up to 12 years after Tdap vaccination in wP-primed Australian adults. There was no evidence that pertussis immune responses waned faster after a booster dose. These findings support current recommendations of repeating Tdap booster vaccination in paediatric healthcare workers at least every 10 years. Clinical trials registry: ACTRN12615001262594.     

Post stem cell transplantation revaccination: A survey of the current practices in India

BackgroundHematopoietic stem cell transplant (HSCT) recipients are more susceptible to infections from vaccine preventable diseases (VPDs) than the general population. Indian stem cell transplant registry (ISCTR) post-BMT vaccination guidelines were formulated in 2015. The objective of the survey was to assess the compliance to these guidelines among transplant physicians in India.Materials and methodsThis is a cross-sectional survey executed as the quantitative research strategy to explore the various aspects of vaccination practices among transplant physicians in India. The ‘data collection tool’ included 36 predetermined questions related to vaccination of the patients and their close contacts. Theoretical construct of the questionnaire was face-validated and questionnaire survey forms were emailed individually as attachments or by google forms. This study is being reported based on the checklist for reporting results of internet e-surveys statement guidelines.ResultsSurvey forms were sent to 105 transplant physicians in India, 62% of whom responded representing 78.8% of transplant centers in India. More than 90% of allogeneic transplant physicians and 64% of autologous transplant physicians offered vaccination. Over two third of the physicians responded that they would discontinue vaccination at the onset of cGVHD. Fewer than one third physicians offered vaccination against Hepatitis A, Typhoid or Meningococcal infections. Forty two percent of respondents were unaware of the ISCTR post-BMT vaccination protocol. Only 47% of respondents reported complete adherence to any of the protocols they were following. Immune reconstitution to guide vaccination was available only to 13.3 percent of respondents.ConclusionThere is a need to improve the implementation strategies of vaccination in HSCT recipients to increase the adherence and continuation of it even in the presence of GVHD. There is also a need to extend the vaccination among VPDs especially prevalent in India.     

Incomplete Immunity and Missed Vaccination Opportunities in East African Immigrants Settling in Australia

Background: Immigrants and refugees are at particular risk of incomplete immunisation and may be unaware of their vaccination status. There is a paucity of data on the immunisation status of adult immigrants from African countries. Aims: To review the immunisation status of adult immigrants from East Africa, and to identify missed opportunities for vaccination. Methods: A community survey was conducted using self-reported vaccination status, Mantoux skin tests, and serological testing for immunity to hepatitis B, tetanus, diphtheria and measles. Results: Proven inadequate immunity against at least one of tetanus (67%), hepatitis B (41%), diphtheria (34%) or measles (3%) was found among 100/126 (81%) participants despite a median of seven visits to vaccine providers since immigration. A positive Mantoux test occurred in 17% of participants. Conclusions: Pre- and post-arrival health assessments are currently failing to address vaccination needs in recently arrived East African adult immigrants. Immigrants should have their immunisation status assessed, with opportunistic vaccination provided wherever possible.     

Vaccination coverage and immunity levels against vaccine-preventable diseases in male Air Force recruits in Greece

AimData about susceptibility rates in young adults are scarce. We estimated the complete vaccination rates, timeliness of vaccinations and susceptibility rates among male military recruits in Greece.MethodsA standardized form was used to collect data. Immunity against measles, rubella, varicella, hepatitis A and hepatitis B was serologically estimated.ResultsWe studied 385 recruits with a mean age of 23.5 years (range: 18.3–29.9 years). Complete vaccination rates were 94.3% for measles, 100% for rubella, 15% for varicella, 73.9% for hepatitis A and 96.5% for hepatitis B. Only 10.8% of participants were fully vaccinated against all five diseases. Timely vaccination was 47.2% for measles, 89.3% for rubella and 48.1% for hepatitis B. Recruits >23 years had a 1.5-fold increased probability for incomplete vaccinations compared to younger recruits. Laboratory-confirmed immunity rates were 80% against measles, 85.7% against rubella, 85.2% against varicella, 69.4% against hepatitis A and 77.1% against hepatitis B. It is estimated that approximately 388,696 persons aged 18–30 years are susceptible to measles, 277,640 persons to rubella, 287,736 persons to varicella, 595,664 persons to hepatitis A and 444,224 persons to hepatitis B in Greece.ConclusionOur study showed that young adults have significant immunity gaps against measles, rubella, varicella, hepatitis A and hepatitis B. Complete vaccination rates were suboptimal against hepatitis A and varicella. Strategies to access young adults and increase immunity rates through catch-up vaccination services should be investigated. A third dose of MMR vaccine should be considered for young adolescents in Greece.     

Seroprevalence of chronic hepatitis B virus infection and immunity to measles,rubella, tetanus and diphtheria among schoolchildren aged 6–7 years old in the Solomon Islands, 2016

The Western Pacific Region (WPR) established a goal to decrease chronic hepatitis B virus (HBV) infection among children to <1% and to achieve ≥95% hepatitis B vaccine birth dose (HepB-BD) and ≥95% three-dose (HepB3) coverage by 2017. In 2016, we conducted a national serosurvey in the Solomon Islands among 6–7-year-old school children to assess progress towards the control goal and immunity to measles, rubella, tetanus and diphtheria. Eighty schools were selected systematically proportional to their 6–7-year-old population; all 6–7-year-olds were enrolled. We collected basic demographic information and vaccination history. Children were tested for HBV surface antigen (HBsAg) using a rapid test, and for immunity to measles, rubella, tetanus, and diphtheria using a multiplex bead assay. In total, 1,249 out of 1,492 children (84%) were enrolled, among whom 1,169 (94%) underwent HBsAg testing and 1,156 (93%) provided dried blood spots. Almost 80% (n = 982) of enrolled children had vaccination cards, among whom 59% (n = 584) received a timely HepB-BD (within 24 hours of birth), 95% (n = 932) received HepB3, and >90% received vaccines for diphtheria, tetanus, and measles (rubella vaccine was not available at the time). HBsAg prevalence was 3.1% (95% confidence interval (CI): 2.0%–4.9%), with 55% of identified cases from one province. Among 982 children with vaccination cards, HBsAg prevalence was higher among children who had not received a timely HepB-BD and at least two HepB doses compared to those who had (4% vs. 2%). Of 1,156 tested children, immunoprotection estimates were 99% (95% CI: 98%–99%) for measles, 99% (95% CI: 97%–100%) for rubella, 85% (95% CI: 83%–87%) for tetanus, and 51% (95% CI: 47%–55%) for diphtheria. Improving timely HepB-BD coverage and maintaining high HepB3 coverage could help Solomon Islands reach the regional HBV control goal. Low immunity to tetanus and diphtheria suggests the need to introduce booster doses to ensure long-term protection.     

Measles seroepidemiology and decay rate of vaccine-induced measles IgG titers in Taiwan, 1995-1997

Community-based seroepidemiologic studies were conducted to monitor the effectiveness of measles immunization programmes and to estimate the decay rate of vaccine-induced measles IgG titres. Sera collected from a mountain (792 sera), rural (875 sera) and urban (894 sera) populations in 1995–1997 were available. Measles IgG was quantified using a commercial EIA kit. Measles IgG seroprevalence and geometric mean titre (GMT) were calculated by setting the cut-off titre at 50 mIU/ml. The decay rate of measles IgG titres was estimated by assuming that the measles IgG titres, without exposing to wild measles virus, decay exponentially and constantly after 1 year post vaccination. The half-life of measles IgG titres was calculated from the corresponding decay rate. Measles IgG seroprevalences in these three populations have reached >95% in school children (7–18 years old) and >98% in young adults (19–25 years old) but varied from 87 to 96% in pre-school children (4–6 years old). Two-dose vaccinees, comparing with 1-dose vaccinees, had a significantly higher seroprevalence (98 versus 92%, P<0.01) and a slightly longer half-life of measles IgG titres (61 versus 27 months, P=0.08) but the measles IgG GMT in the two groups did not differ significantly (675 versus 618 mIU/ml, P=0.78).     

Effects of measles-control activities--African region, 1999-2005

In 1999, of approximately 871,000 deaths from measles worldwide, 61% occurred in sub-Saharan Africa. In 2001, countries in the World Health Organization (WHO) African Region began an accelerated measles-control program to reduce by half by 2005 the number of deaths that were caused by measles in 1999. The African Region accelerated measles-control program was based on four strategies: improving routine vaccinations; providing a second opportunity for measles vaccination through a routine, 2-dose vaccination schedule or through supplementary immunization activities (SIAs); improving measles case management; and establishing case-based surveillance with laboratory confirmation for all suspected measles cases. Seven countries in the region had already completed catch-up SIAs by 2000, before the regional program began; in 2001, additional countries in the region began implementing catch-up, and later, follow-up SIAs, and steps were taken to improve routine vaccination coverage with measles vaccine and other vaccines in the Expanded Programme on Immunization schedule. This report summarizes the nationwide SIAs and other measles-control activities conducted in the WHO African Region during 1999-2004, analyzes the trends in reported measles cases since 1990, and compares the annual number of measles cases reported in 2005 with those reported in 1999.     

A programme of multiple-antigen childhood immunization in Yaoundé, Cameroon: first-year evaluation, 1975-1976.

The Yaoundé multiple-antigen childhood immunization programme began in November 1975, making it one of the first expanded programmes on immunization operational in Africa. During the first 9 months, more than 22 000 children were immunized against poliomyelitis, measles, tuberculosis, smallpox, whooping cough, tetanus, and diphtheria. Evaluation of the programme showed the following rates of immunization coverage in the target population; 30% for DPT (one dose or more), 27% for poliomyelitis (one dose or more), 27% for BCG, 33% for measles, and 20% for smallpox. Eighty per cent of children received the correct vaccines for their age and vaccination status. Seroconversion to measles vaccine was 89% in those over 12 months of age but only 50% in those between 6 and 11 months of age. The major factor in low immunization coverage was felt to be inadequate publicity. The cost of the programme was estimated to be US $10 920. The cost of immunizing a child completely was estimated at US $1.90. Some logistic problems encountered during this initial year of operation are discussed.