A study was carried out in Gweru urban district (population-158233) in Zimbabwe to determine the impact of measles vaccine applied at 9 months of age on measles transmission patterns. A retrospective observational study that used data from measles vaccination records and measles disease surveillance was conducted. Linear regression analysis and the chi-squared test for linear trend (χ2) were used to investigate linear relationships at a 5% significance level. Vaccine coverage rates were 0% in pre-vaccination era in 1960-70 and 2-92% in 1971-89 (median=65, Q1=34, Q3=88) when they significantly linearly increased (p<0.001). In 1960-85 measles incidence rates significantly linearly increased (p<0.001) while in 1986-89 at vaccine coverage rates of >90% incidence rates significantly linearly declined (p<0.001). Proportion of vaccinated cases among measles notifications significantly linearly increased as vaccine coverage rates increased (Slope: +1.19, 95% CI [0.52, 1.86]). At vaccine coverage rates of >80% (1984-89), proportion of vaccine failures among cases aged 60-119 months was significantly higher than at vaccine coverage rates of <80% (1971-83) (p=0.011) while in age group 10-59 months proportions of vaccine failures were not different at vaccine coverage rates of <80% and >80%. In age group 60-119 months incidence rates significantly linearly increased as vaccine coverage rates increased (Slope: +29.88, 95 CI [13.95, 45.82]). In pre-vaccination era, and at vaccine coverage rates of <80% and >80% some 75% of all reported measles cases occurred by age 36-47 months, 48-59 months and 72-83 months respectively. In conclusion, measles incidence rates declined at vaccine coverage rates of >90%, while measles vaccine failures significantly increased as vaccine coverage rates increased. Increasing measles vaccination coverage led to shift of age at infection from age group <59 months to age group 60-119 months and decline in rates of measles transmission.

Introduction A study compared rates of measles transmission and force of infection in pre-vaccination era (1967), and at measles vaccine coverage rates of 50-80% (1978-84) and > 90% (1989). Using measles surveillance data cumulative proportions of measles cases by age were determined for the years 1967, 1978-89 (pooled) and 1989. From the cumulative curves estimates of the age dependent rate of infection with measles (force of infection) was determined for the years 1967, 1978-84 and 1989. Results In 1967 and 1978-84 some 75% of all measles cases occurred by age group 36-47 months while in 1989 this occurred by age group 72-83 months thus measles transmission was most rapid in 1967 and least rapid in 1989. Variation of force of infection between years 1967, 1978-84 and 1967 showed that force of infection was not significantly different between the years for age groups 24-35, 36-47 and 48-59 months. Meanwhile, the force of infection varied between the years in the rest of the age groups, with a significant reduction in force of infection over the years for age groups < 11, and 12-23 months; and significant increases in force of infection were observed in the age groups 60-71, 72-83, 84-95, 96-107 and 108-119 months. Conclusion Measles transmission rates in the community were highest in pre-vaccination era and least at vaccination coverage rates of > 90% most likely due to effect of herd immunity. From pre-vaccination era (1967) to vaccine coverage rates of > 90% (1989) there was a shift in force of infection from young age groups < 23 months to older age groups of 60-119 months most likely due to accumulation of susceptibles in these older age groups. Shift in force of infection to older age groups would have been responsible for the shift in age at infection to these older age groups.

A study was carried out to determine secular changes in all-cause mortality rates for children aged < 5 years in 1960-1989 and their association with measles and malnutrition mortality rates in the same age group in the same period in city of Gweru, Zimbabwe. The study utilized under-fives mortality data from births and deaths registration office and measles and malnutrition surveillance data obtained from Gweru city’s public health department. Data was analysed in SPSS version 20 for windows and linear regression analysis was used to determine whether measles and malnutrition mortality rates were independent predictors of all-cause underfives mortality rates. It was found that in 1960-1989 underfives mortality rates from all causes were 10.2-63.7/1000 live births (median: 28.7, Q1 = 16.2, Q3 = 42.6) and these rates significantly and linearly declined in this period (χ2 for linear trend=165.74, p < 0.001). Measles mortality rates among underfives significantly and linearly declined (χ2 for linear trend = 812.49, p<0.001) while malnutrition mortality rates in the same age group also significantly and linearly declined (X2 for linear trend = 2411.54, p<0.001) in underfives in 1960-1989. Linear regression analysis indicated that malnutrition mortality rates (Regression Coefficient = 0.072, 95% CI = 0.039 - 0.104, p < 0.001) and measles mortality rates (Regression Coefficient = 0.029, 95% CI = 0.006-0.052, p=0.02) were independent predictors of all-cause underfives mortality rates with an adjusted coefficient of determination of 70.5% (Adjusted R2 = 0.7048) with malnutrition mortality rates uniquely explaining 21% of the variance in all-cause mortality (semipartial correlation squared = 0.21) while measles mortality rates uniquely explained 7% of the variance in all-cause mortality rates (semipartial correlation squared =0.068). It was concluded that decline in malnutrition and measles mortality rates among underfives significantly contributed to decline in all-cause underfives mortality rates in 1960-89 in Gweru city, Zimbabwe. On account of these findings, it is critical that efforts directed at controlling malnutrition and measles be intensified in areas and populations of similar settings.

Background: Multiple dose measles vaccination intervention was applied in Gweru City, Zimbabwe, in 1990-96, following a single dose applied at 9 months of age during 1983-89. In the same periods in Bulawayo, only a single dose of measles vaccine was applied to children at 9 months of age. This study investigated the impact on measles transmission patterns of multiple dose measles vaccination strategy. Study design: Quasi-experimental community intervention applied in Gweru city with Bulawayo city as a control. The intervention included a single mass vaccination campaign carried out in1990 targeted at children aged 12-119 months irrespective of their vaccination status or disease history. Children born after 1990 were vaccinated at 9 months of age plus another single dose applied at any point between ages of 12 and 23 months (revaccination). Subjects: Measles cases were identified in both cities through surveillance. Results: Mean coverage rates for measles vaccine applied at 9 months of age were in 1983-89 85.7% and 84.6% in Bulawayo and Gweru respectively, while in 1990-96 they were 89.0% and 89.7%, respectively. In both periods the vaccine coverage rates were not significantly different in the two cities (p=0.464). In the 12-23 months age group, Gweru measles vaccination coverage rate in 1990 was 83% for single dose and 82.4% for second dose in 1990-96. Measles incidence rates in 1983-89 in both cities significantly declined and were not significantly different (p=0.898). Median incidence rates of measles in1990-96 were 131.0 and 19.0/100 000 population in Bulawayo and Gweru respectively and these were significantly different (p= 0.021). Bulawayo had measles epidemics in 1992, 1993, 1994 and 1996. In Bulawayo in 1993-96 vaccinated measles cases accounted for a median of 58% of all reported cases aged 10-119 months. Median incidence rates of measles among vaccine failures aged 10-119 months in 1993-96 in Bulawayo and Gweru were 419.1 and 13.1/100 000 population respectively and these incidence rates were significantly different (p= 0.021). In Bulawayo in 1993-96 cases aged 60-119 months accounted for a median of 56.5 % of all reported cases. Median incidence rates of measles among cases aged 60-119 months in 1993-96 in Bulawayo and Gweru were 869.9 and 26.9/100 000 population respectively and these rates were significantly different (p=0.021). Conclusion: Multiple dose vaccination strategies led to significantly reduced measles transmission in Gweru (compared to Bulawayo) in 1990-1996 by minimizing occurrence of vaccine failures and occurrence of cases in older children aged 60-119 months.

A retrospective study conducted in Gweru, Zimbabwe, investigated the trend and its associated factors in measles mortality between 1967 and 1989. Measles and malnutrition surveillance data were analysed in SPSS version 8.0 using the Forward Stepwise Linear Regression method. Measles case fatality rates ranged from zero to 48.2% (median: 4.2, Q(1) = 1.2, Q(3) = 12.9) and they significantly linearly declined [slope = -1.686; 95% confidence interval (CI) -2.327, -1.044; R(2) = 59%]. Rates of mortality among complicated measles cases (slope = 0.546, 95% CI = 0.133-0.345) and rates of mortality from malnutrition among children aged <5 years (slope = 0.459, 95% CI = 0.031-0.099) independently predicted (R(2) = 87%) measles case fatality rates. It was concluded that decline in rates of mortality among complicated measles cases, probably due to good management of such cases, and decline in rates of malnutrition among children aged <5 years may have contributed to the decline in measles case fatality rates.

Zambia has a population of approximately 12 million. According to estimates from the 2001-2002 Zambia Demographic and Health Survey1 between 1997 and 2001 the rate of neonatal mortality was 37/1000 births the infant mortality rate was 95/1000 births and the maternal mortality ratio was 729/100 000 live births. In order to protect mothers and their newborn babies against tetanus WHO recommends that tetanus toxoid (TT) vaccine be given to all pregnant women; Zambia follows WHOs recommendations. In 2006 79% of all pregnant women received a protective dose of TT vaccine. A total of 60% of all deliveries took place in hygienic conditions (administrative data). WHO and UNICEF estimate that in 2006 90% of births were protected against tetanus. (excerpt)

OBJECTIVETo investigate factors associated with complications or death among measles cases.DESIGNA cross-sectional study.SETTINGHealth facilities in the city of Gweru, Zimbabwe.SUBJECTSSix hundred and thirty seven measles cases randomly selected from measles surveillance data.MAIN OUTCOME MEASURES(a) Associations of respiratory complications and diarrhoea with death among complicated cases; (b) associations of age at infection, gender of cases and vaccination status of cases with occurrence of either respiratory complications or diarrhoea or death among measles cases.RESULTSAmong cases with respiratory complications, twenty two (29%) had died, while five (5%) had died among those with diarrhoea (OR=7.06,95% CI=2.55-22.35, p<0.001). On rates of respiratory complications among cases, age groups 24-59 and 60+ months were protective by 57% (95% CI=11-79%) and 76% (95% CI=52-88%) respectively compared to the age group <24 months, and vaccination was protective by 42% (95% CI=2-65%) compared to those unvaccinated. Concerning rates of diarrhoea among cases, the age group 60+ months was protective by 80% (95% CI=62-89%) compared to age group <60 months, while vaccination was protective by 64% (95% CI=42-77%) compared to those unvaccinated. With respect to rates of mortality among cases, age was protective by six per cent (95% CI=3-9 %) for every year older.CONCLUSIONIt was concluded that: (a) the risk of death was higher in cases with respiratory complications than diarrhoea; (b) the risk of complications and death was inversely related to age at infection and older age groups were protective against occurrence of complications or death; (c) the risk of complications was higher in unvaccinated cases and vaccination was protective against occurrence of complications.

Multiple dose measles vaccination was applied in Gweru, Zimbabwe in 1990-1996. This included (a) a vaccine administered to children at 9 months of age and revaccination of the same children at any point between the ages of 12 and 23 months, and (b) a single mass vaccination campaign targeted at children aged 12-119 months (who were vaccinated irrespective of vaccination status or disease history) run in early 1990. This study describes the impact of this schedule on measles transmission patterns. Using measles disease surveillance data the study compared measles transmission patterns under single dose vaccination in 1983-1989 and under multiple dose vaccination in 1990-1996. Median measles incidence rates were 261.0 and 19.0/100000 population in 1983-1989 and 1990-1996, respectively, and these were different (p = 0.002). Vaccinated cases (vaccine failures) among children aged 10-119 months significantly increased from 49.6 to 70.4 per cent of all reported cases in 1983-1989 and had a median incidence rate of 480.4/100000. In 1990-1996 the median incidence rate was 12.8 and these incidence rates were different (p = 0.002). Cases aged 60-119 months significantly increased from 14.3 to 62.2 per cent of all reported cases in 1983-1989 and had a median incidence rate of 654.1/100000. In 1990-1996 the median incidence rate was 21.4 and these incidence rates were different (p = 0.004). It was concluded that under multiple dose vaccination, lower measles incidence rates occurred most likely due to reduction of both vaccine failures and cases aged 60-119 months.

OBJECTIVES:To characterize the nature and extent of the outbreak; to determine the risk factors associated with contracting shigellosis; and to institute disease control and preventive measures.DESIGN:Case control study.SETTING:Nyaure Ward, Goromonzi District, Mashonaland East Province, Zimbabwe.SUBJECTS:52 cases and 52 controls. A case was defined as any resident of Nyaure Ward who presented with bloody diarrhoea (three or more loose stools/day) between 25 July and 25 October 1997.MAIN OUTCOME MEASURES:Frequencies of symptoms, types of treatment received, risk factors for contracting the illness.RESULTS:The median age was 17 (Q1 = 8, Q3 = 30) years for cases and 19 (Q1 = 7, Q3 = 28) years for controls. Prominent symptoms were abdominal cramps (96.2%), malaise and fever (92.3%), nausea and vomiting (50.0%). The median duration of diarrhoea was 13 (Q1 = 6, Q3 = 14) days. Eighteen (34.6%) cases were admitted and of these five were referred to a central hospital and two of them complicated with haemolytic uraemic syndrome. The case fatality rate was 1.6%. Twenty four(46.1%) of the cases had Shigella dysenteriae type I, sensitive to Nalidixic acid, Kanamycin, and Doxycycline but resistant to Metronidazole, isolated from the stool specimen. Water samples did not yield any pathogens. Significant risk factors associated with contracting dysentery were shared hand washing in the same standing water at gatherings[OR = 8.47, 95% CI: (2.43-31.33)] or within homes[OR = 60.43, 95% CI: (15.73 to 256.00)]. The use of Blair toilets was a protective factor[OR = 0.03, 95% CI: (0.01 to 0.11)].CONCLUSION:The epidemiologic evidence implicated contamination of water used for shared hand washing before meals as the source of the infection. The common practice of shared hand washing in standing water should be discouraged at all gatherings and within households to avoid future outbreaks.

A cross sectional study was conducted to determine occupational factors associated with the human immunodeficiency virus (HIV)) infection. The survey covered 30 health institutions throughout Zambia. A total of 370 consenting midwives took part in the study. The main outcome measures were percentage of midwives reporting adverse occupational exposures and HIV status. Out of 370 midwives, 146 (39.5%) were positive for HIV infection. Of the 370 respondents, 48 (13.0%) thought that they were HIV infected. None of these 48 midwives thought she became infected because of occupational exposure to HIV infected blood. A total of 324 (87.6%) said that they were concerned about becoming HIV positive at work. ;Needle stick injury' was reported by 321 (88.2%) midwives. The percentages of midwives reporting hand washing after every contact with a patient, using gloves all of the time and wearing aprons were 54.0%, 53.7% and 44.1% respectively. None of the occupational factors was associated with HIV infection. In conclusion, although there was no evidence to suggest occupational exposure to HIV among midwives, adherence to universal precautions was poor. Midwives should be educated about these precautions.

OBJECTIVE:To determine levels of perceived risk of HIV infection and the determinants of these perceptions among commercial farm workers.DESIGN:Cross sectional.SETTING:Commercial farms in Manicaland, Mashonaland Central, Mashonaland West and Mashonaland East provinces of Zimbabwe.SUBJECTS:406 male and 411 female adults.MAIN OUTCOME MEASURES:Perceived risk of HIV infection.RESULTS:Out of 33 female respondents aged less than 20 years, 19 (57.6%) reported that they had no chance of acquiring the HIV infection. The majority (15) of these 19 teenagers indicated that they had no chance of being HIV infected because they had sex only with their spouses. Of the respondents aged 20 years or more, 235 (64.6%) males and 182 (55.3%) females reported that they had no chance of being HIV infected (OR = 1.47, 95% CI 1.07 to 2.02, p = 0.016). Most males (57.0%) and females (59.9%) of age 20 years or more said that they had no chance of being HIV infected because they had sex with only their spouses. Among the respondents of age 20 years or more who indicated they had a moderate to high chance of being infected or were already infected, 35 (33.3%) of the males reported that they had multiple partners and 41 (40.6%) of the females reported that their spouses had multiple partners.CONCLUSION:In general, despite high seroprevalence rates in Zimbabwe, many individuals do not perceive themselves at risk. Future health education intervention studies should seek to increase the general perception of low risk so that adequate precaution can be taken against being infected.

It has been observed that the occurrence of respiratory complications and diarrhoea among measles cases has changed over time but this change has not been quantified. A study was carried out in the city of Gweru, Zimbabwe, to quantify these changes. Rates of respiratory complications and diarrhoea among measles cases were determined in each year for the period 1968-89. It was found that mean rates of respiratory complications and diarrhoea during 1968-78 were 17.2 per cent (95 per cent CI = 11.6-22.8) and 5.2 per cent (95 per cent CI = 0-11) respectively while during 1979-89, mean rates of respiratory complications and diarrhoea were 6.5 per cent (95 per cent CI = 1-12.1) and 16.4 per cent (95 per cent CI = 10.1-22.0) respectively. Analysis of variance (ANOVA) to determine the main effects and the interaction showed that the main effects were not statistically significant (F = 0.01, d.f.1,2 = 1,40, p = 0.935; and F = 0.13, d.f.1,2 = 1,40, p = 0.725 respectively) Meanwhile the interaction term of complications and period was statistically significant (F = 15.7, d.f.1,2 = 1,40, p < 0.001). It was concluded that a change in rates of respiratory complications and diarrhoea had occurred among measles cases. It is suggested that the increase in vaccination coverage in 1979-89 and the shift in age at infection to older age groups in the same period may have brought about this change through selective suppression of respiratory complications among measles cases.

OBJECTIVE:To quantify the main reasons for referral from urban primary health care clinics to central hospitals and to assess the outcome of such referrals in Bulawayo.DESIGN:Descriptive cross sectional study.SETTING:Mpilo Central Hospital, a quaternary level hospital and referral centre for urban clinics.SUBJECTS:914 patients referred by urban clinics who attended the hospital in April and May 1995.MAIN OUTCOME MEASURES:Frequency of referrals by referrer, reasons for referral, outcome of referrals, diagnosis of admitted referrals.RESULTS:Of 914 referrals studied, 863 (94%) were made by registered general nurses and 51 (6%) by medical officers. Four hundred and forty four (49%) referrals made by registered general nurses were for doctors to establish the diagnosis, and 341 (37%) were for treatment or operation. The other referrals were for specialists to take over management, for advice on management and referral back to the clinic, and for the hospital to carry out specific tests. Of all referrals, 844 (92%) were consulted by generalist medical officers (GMOs), and only 70 (8%) by specialists. A total of 148 (16%) patients were admitted. Of these, 84 (57%) were females and 47% of admissions were aged 15 years or more. Nine (18%) of 51 referrals made by medical officers were admitted compared to 139 (16%) of 863 by registered general nurses. The rate of admission was not different by referrer (p = 0.7).CONCLUSIONS:The main reasons for referral from urban clinics to central hospitals are for doctors to either establish the diagnosis or provide treatment. There is scope for reducing the number of referrals made primarily for these reasons if a secondary or tertiary level of care institution is availed to Bulawayo and/or if clinic operations are reorganized to make medical officers' advice more accessible to registered general nurses during working hours.

OBJECTIVE:To quantify changes in measles transmission patterns. DESIGN:Analysis of measles surveillance data. SUBJECTS:All measles cases identified in 1988. MAIN OUTCOME MEASURES:Proportion of cases in age group 60 to 119 months, proportions of vaccinated and unvaccinated cases in age group 60 to 119 months, and occurrence of cases in schools. RESULTS:Measles vaccination coverage was 91%. Incidence rate of measles was 205 per 100,000 population. The age group 60 to 119 months accounted for 49% of all reported cases and 68% of cases in this age group were vaccinated. There were measles epidemics in schools and these were associated with occurrence of secondary cases in younger siblings in the community. Case fatality rate and mortality rate were 0.4% and one per 100,000 population respectively. CONCLUSION:High measles transmission in children of school going age could spill into the community through generation of secondary cases among younger siblings and this could result in high morbidity and mortality in this vulnerable group. It is recommended that either revaccination at school entry or mass vaccination campaigns be carried out in affected age groups at schools to reduce occurrence of epidemics.

We conducted a further analysis of the Zimbabwe 1994 demographic health survey data to determine demographic and social factors associated with adolescent pregnancies in Zimba notbwe. Out of a total of 1486 female adolescents sampled, 12 did not provide information on whether they had begun child bearing, and were therefore excluded from the analysis. Significantly elevated odds ratios (OR) were noted for age (OR=2.27,95% confidence interval (CI) 2.01-2.58) and having primary or no education (OR=1.58, 95%CI 1.35,1.87). Watching television every week was protective (OR=0.69, 95%CI 0.57-0.83). Heads of households with less than 25 years of age were 2.10 (95%CI 1.54-2.87) times more likely to have adolescents who were pregnant when compared with heads of households of age 35 years or more. We conclude that electronic media should be continued to be used to deliver sex education messages to adolescents in order to curb the adolescent pregnancy epidemic.

OBJECTIVE:To determine the effect of rates of complications among cases and management of complicated cases on measles case fatality rates.DESIGN:Measles disease surveillance.SETTING:City of Gweru, Department of Health.SUBJECTS:Children aged zero to 15 years.MAIN OUTCOME MEASURES:Case fatality rates.RESULTS:Measles case fatality rates declined from 47.6 in 1967 to zero in 1989. Between 1967 and 1978 respiratory infections were the predominant complications (66.5%), while after 1979 diarrhoea was the predominant complications (60.6%). A significant partial correlation coefficient was observed between rates of mortality among complicated cases and case fatality rates (r = 0.89, df = 20, p < 0.001).CONCLUSION:Good management of complicated cases may have contributed towards the decline in measles case fatality rates.

An intervention study compared the protection afforded vaccinees by single measles vaccination and late revaccination schedules in 1990-94. During the intervention a single revaccination (after initial vaccination at nine months of age) was applied to children at any point in time between 12 and 23 months of age. Cases of measles aged 10-23 months were identified through an active surveillance system and in this period 5, 11 and 11 cases of revaccinated, single vaccination and unvaccinated children were identified. Measles incidence rates were 392.2-415.6 (mean = 405.6, SD = 6.7), 75.4-112.1 (median = 91.7, SD = 13.3) and 12.8-15.2 (mean = 13.9, DS = 0.99) per 100,000 population in children who were unvaccinated, with single vaccination and revaccinated respectively. Relative risk of contracting measles in children who were unvaccinated or with single vaccination was 26.5-32.5 (mean = 29.4, SD = 2.3) and 5.8-8.8 (mean = 6.8, SD = 1.2) respectively compared with revaccinated children. Vaccine efficacies that were determined were 73-81% (mean = 77.2, SD = 2.9) and 96.2-96.9% (mean = 96.6, SD = 0.27) for single vaccination and late revaccination schedules respectively. It was concluded that late revaccination affords vaccinees better protection than single vaccination through improvement in vaccine.

A comparative study was conducted in northern Zambia in order to compare both the economical and diagnostic performance of a questionnaire with that of the chemical reagent strip test in diagnosing urinary schistosomiasis with a view to replacing the more economically expensive reagent strip test with the questionnaire in the identification of high risk communities. A total of 57 schools participated in the study and each school was considered as a community. Among the symptoms and conditions of blood in urine, pain when passing urine and bilharzia for urinary schistosomiasis, blood in the urine was the best predictor for urinary schistosomiasis with 73.9 pc (95 pc CI 56.0 to 91.9 pc) sensitivity, 82.4 pc (95 pc CI 69.5 to 95.2 pc) specificity and 78.9 pc (95 pc CI 68.4 to 89.5 pc) diagnostic efficiency in the identification of schools with high levels of infection. A diagnostic questionnaire for urinary schistosomiasis was two times cheaper than the reagent strip test in economical terms. The questionnaire approach in identifying high risk communities for urinary schistosomiasis is promising and should be tried in other endemic areas.

OBJECTIVE:To carry out a survey in Masvingo District to determine the efficacy of measles vaccine.DESIGN:A retrospective study, using existing health care facility records and interviews with care givers.SETTING:Using the standard WHO-EPI cluster sampling methodology, 30 clusters were randomly selected in Masvingo District.SUBJECTS:14 or more children in each of the 30 clusters were selected.MAIN OUTCOME MEASURES:Occurrence of measles or lack of it among the children aged 12 to 23 months, age at vaccination, status, the age at which the child had measles and availability of a health card.RESULTS:In Masvingo District from 1987 to 1994, measles incidence remained very high, though mortality drastically declined. Using field survey data measles vaccine efficacy was estimated at 78.3pc (95pc CI 54.1; 89.8). Vaccine coverage was estimated to be 75pc.CONCLUSION:The efficacy results fall at the lower end, but within the normal limits, of those expected for measles vaccine as used in Zimbabwe. Steps to increase vaccine coverage are of the highest priority.