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Termination of the coronavirus pandemic by vaccination will be heralded as a triumph for science. Indeed, vaccines are an incredible intervention, freeing us from the harms caused by a swathe of diseases. A vaccine is a classical biomedical intervention, in this case targeted against a specific virus. The development of Koch’s postulates for determining whether a specific microorganism is the cause of a given disease, and the work of Louis Pasteur, were key elements in the development of the model, which didn’t just lay the basis for the development of vaccines, but also formed the bedrock of modern medicine. The biomedical approach relies on categorising patients through agreed, standardised criteria for diagnosis, thence providing a basis for the development of effective treatments. Infectious diseases and a wide range of other conditions have been classified …

This article describes estimation and inference procedures for the parameters of the Box-Cox and foided-power transformations in repeated measures and growth curve models. Procedures for computing maximum likelihood estimates of the transformation and covariance parameters under several covanance structures (omnibus sphericity, local sphericity, and unstructured) are described. Lack of fit statistics and hypothesis tests for comparing these structures also are described. The procedures are illustrated on three data sets. Software for performing the analyses in the SAS System is described and is available from the authors.

Iodized salt and iodized oil are the main methods used to prevent iodine deficiency, but sometimes alternative approaches are needed. We tested the efficacy of various regimens for the intermittent administration of potassium iodide in Hwedza, Zimbabwe, an area of known severe iodine deficiency. We divided 304 schoolchildren aged 7-13 y into five equal groups that received iodine as a 10% solution of potassium iodide as follows: 8.7 mg every 2 wk (group A), 29.7 mg every month (group B), 148.2 mg every 3 mo (group C), 382 mg every 6 mo (group D), or 993 mg once (group E). The follow-up period was 13 mo. No adverse effects were encountered with any of these doses. After 6 mo, the median blood spot thyroglobulin concentration had decreased in all groups and had normalized in groups A and B to values found in iodine-sufficient populations. The number of children with elevated thyroid-stimulating hormone concentrations decreased in groups A-C, but the changes were not significant. Urine iodine concentration generally remained low in all groups but increased in group A. After 13 mo, mean thyroid volume measured by ultrasound had decreased in groups A and B to values comparable with those in iodine-sufficient areas, and was unchanged in the other groups. We conclude that oral potassium iodide is effective for the prophylaxis of iodine deficiency if given as a dose of 30 mg I monthly or 8 mg biweekly.

There is national and international interest in increasing the community-based component of undergraduate medical education, but more research is needed on its potential, practicability and effectiveness. The objective of the study was to examine the feasibility and efficacy of general practitioners teaching basic clinical skills to first year clinical medical students in the community. The structure and methods of evaluation of the programme are described. Evaluation tools included semistructured interviews of general practitioner tutors; student questionnaires; assessment of student performance; and costs of the programme. The great majority of the students found the programme enjoyable (81 out of 81, 100%) and educational (79 out of 81, 97%). Students' performance in the end of rotation Objective Structured Clinical Examination suggested that clinical skills are acquired at least as well in the community as in the hospital. Tutors identified the personal benefits of this teaching as development of their own clinical skills and the stimulation of teaching. The programme has been successfully expanded from 24 students to 230 students annually and has demonstrated that community-based teaching can usefully contribute to undergraduate medical education in the area of clinical skills teaching. Key practical issues for schools contemplating similar initiatives are presented.

Immune thrombocytopenic purpura (ITP) and breast cancer are common disorders. Only six cases in which patients have had both diseases have been reported. We describe a 40-year-old woman who had ITP while responding to therapy for metastatic breast cancer. Given the few reported cases, the diverse presentations of thrombocytopenia during the course of each patient's breast cancer and the variable therapeutic responses of ITP, the association of breast cancer and ITP is probably coincidental.

Chronic obstructive pulmonary disease (COPD) is a disease state characterised by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases. Classically, it is thought to be a combination of emphysema and chronic bronchitis, although only one of these may be present in some people with COPD. The main risk factor for the development and deterioration of COPD is smoking.We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of maintenance drug treatment in stable COPD? What are the effects of smoking cessation interventions in people with stable COPD? What are the effects of non-drug interventions in people with stable COPD? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).We found 119 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.In this systematic review, we present information relating to the effectiveness and safety of the following interventions: alpha(1) antitrypsin, antibiotics (prophylactic), anticholinergics (inhaled), beta(2) agonists (inhaled), corticosteroids (oral and inhaled), general physical activity enhancement, inspiratory muscle training, nutritional supplementation, mucolytics, oxygen treatment (long-term domiciliary treatment), peripheral muscle strength training, psychosocial and pharmacological interventions for smoking cessation, pulmonary rehabilitation, and theophylline.

Zimbabwe’s Government of National Unity (GNU), established on Feb 13, 2009, faced immense challenges: a collapsed economy with 94% of the population without a job and almost 50% needing food aid; a severe cholera epidemic; HIV/AIDS prevalence of more than 15% in adults aged 15–49 years; and a collapsed health system. The GNU responded to the issues of the health sector by holding an inclusive summit and adopting an ambitious 100-day recovery plan for the health sector. Here, we describe the recent health crisis and its causes, and make proposals for an eff ective and sustainable health system. Zimbabwe was once a beacon of hope in Africa, improving health tremendously after independence in 1980. A declining national income, a huge national debt, economic structural adjustment, recurrent droughts, widespread HIV/AIDS, and a weakening health system all contributed to the deterioration of Zimbabweans’ health since 1990. Between 2000 and 2005, the gross national income (GNI) per head declined by 54%. The latest estimate of US$340 places Zimbabwe among the world’s poorest countries: all the income gains of the past 56 years have been wiped out. Economic decline has driven the exodus of Zimbabweans, with over 3 million of the total population of 13·5 million estimated to be living outside the country; the funds remitted by them are the main source of income for many families. For those having no access to external funds the situation is dire. Between 1990 and 2006, life expectancy at birth plummeted from 62 to 43 years, mostly from increased young adult mortality from HIV-related conditions. Mortality rates of children younger than 5 years and infants rose from 77 and 53 per 1000 livebirths in 1992 to 82 and 60 in 2003, respectively. Maternal mortality rose from 168 per 100 000 births in 1990 to 725 per 100 000 in 2007. Tuberculosis incidence increased from 136 per 100 000 in 1990 to 557 per 100 000 in 2006. These indicators are related to the high prevalence of HIV/ AIDS, which was estimated at 26% in 2000 in adults aged 15–45 years but declined to 15·3% by 2007. In 1994, 80·1% of children aged 12–23 months had received all basic vaccines compared with 74·8% in 1999 and only 52·6% in 2006–07. By early 2009, hospitals in the country were hardly operating, with massive shortages of essential medicines and supplies. Although most hospitals are now functioning again, shortages are still commonplace and patients usually need to buy medicines, intravenous fl uids, and sutures. Women delivering in rural clinics must bring candles, cotton wool, methylated spirit, gloves, and even fresh water. The physical infrastructure of most government health facilities is decrepit, and ambulances sparse. The recent cholera outbreak further exposed Zimbabwe’s collapsed infrastructure and its health system. Between August, 2008, and July, 2009, 98 591 suspected cholera cases were reported, including 4288 deaths. The epidemic resulted from the breakdown of urban water and sanitation systems, leading to contamination of piped water and shallow wells. The case-fatality rate peaked at almost 6%, greatly exceeding the 1% WHO norm, indicating the weakened health system and poor access in rural areas. Total health expenditure per head fell by 56% between 2000 and 2005 to $21, of which $9 was government expenditure. External funding contributed 21% of total health spending, a low proportion compared with that in most African countries. Under the previous government, which was led by Zimbabwe African National UnionPatriotic Front (ZANU-PF) party, bilateral donors channelled funds to specifi c activities such as HIV programmes and family planning. Therefore, 58% of currently married women use modern contraceptive methods, and about 100 000 people were receiving antiretroviral treatment by the end of 2007. However, antiretroviral treatment coverage at 17% is the lowest of any country in southern Africa, with an estimated 570 000 people needing treatment. Furthermore, HIVpositive patients displaced by political violence and those aff ected by stock-outs of common AIDS medicines or closure of treatment facilities have been unable to reestablish treatment. In 2005, Zimbabwe was losing an estimated 20% of its health-care professionals every year; 18 000 nurses have left since 1998. Although some heroically continued to work for minimal rewards, by the end of 2008 many had stopped working. By this time, a government doctor’s salary had fallen to less than $1 per month. Many health workers witnessed violence and some were harassed for treating victims of violence. Health training in Zimbabwe has suff ered badly and the country’s principal medical school—the College of Health Sciences of the University of Zimbabwe in Harare—closed from November, 2008, to May, 2009. Only 40% of academic posts are fi lled; Bulawayo’s new medical school faces even greater staff shortages. Nursing and midwifery schools struggle with 60% of nurse tutor posts vacant. Disregard for human rights has long featured in Zimbabwe’s history. After the elections in March, 2008, thousands of people were beaten or tortured in an attempt to subdue support for the opposition. Political abductions and intimidation continue despite the establishment of the GNU. National recovery cannot take place without addressing human rights and ending the culture of impunity. To restore Zimbabwe’s health sector, the priority must be to meet the population’s most urgent health needs by Lancet 2010; 375: 606–09

One-hundred-and-eighty-eight ostensibly normal, pubertal schoolchildren, aged 9-16 years, residing in Chinamora Communal Land, Zimbabwe, had blood taken to assess thyroid function. Total goitre rate in the area was 44 per cent in primary schoolchildren: 91 of the subjects tested were goitrous. Thyroid stimulating hormone levels (TSH) were above normal (5.0 mu/l) in 66 subjects overall, of whom 39 were goitrous. The 36 subjects with TSH levels above 7.0 mu/l also had total thyroxine (T4) estimations performed: of these, 19 were below 60 nmol/l. The results indicate a high prevalence of hypothyroidism in this at risk group. The implications of these results are discussed, notably the impairment of mental function that is likely to result.

Inferences about fixed effects in mixed linear models are important in a variety of animal science studies. The statistical theory for making such inferences is well known, and if the variance components are known up to a proportional- ity constant, then optimal exact tests can be per- formed. Computing the test statistics, however, can still be problematic when the random effects have many levels. In practice, approximate tests that are easily computed but less efficient are usually em- ployed. This article describes reduction in error sum of squares procedures for performing the exact test and for computing associated confidence intervals. By taking advantage of iterative algorithms for solving Henderson's mixed-model equations, the tests can be performed without inverting the covariance matrix or computing a generalized inverse of the mixed-model coefficient matrix. The procedures are illustrated on an animal model that has three random effects, two with 1,372 levels and one with 450 levels.

Editor,--I would urge that donations of medical supplies to Third World countries should be chosen just as carefully as those to the former Yugoslavia.1 In Zimbabwe I worked at a mission hospital where some of the donations we received included lorazepam, drops for infant colic, and decongestant …

Learning leads to a decrease in program cost and inflation leads to an increase in program cost. At a certain time, the benefits of leaming and the penalty due to inflation will balance each other. This time is defined as the “critical time.” The “critical tune” depends upon the number of ships to be built because this determines the possible gain in learning. The “Critical time” also depends upon the assumed inflation, upon the achievable learning rate, and upon the material/labor ratio of the first ship. Learning expectation can be influenced by planning and the material/labor ration by a make– or buydecision. Assumptions on future learning are as vague as assumptions on inflation. The paper shows that it is almost impossible to beat inflation. It shows that accelerated programs are preferable and that make—decisions supersede the value of buy—decisions. The result is derived from an abstract treatment of the subject.

It has been shown in previous communications (Todd, 1930, a, b ) that the red blood corpuscle of the domestic fowl constitutes a “multiple antigen” of considerable complexity and of so high a degree of specificity that, in unrelated birds, the red cells of any particular fowl can be differentiated from those of any other individual of the same species, by means of a simple agglutination reaction carried out with suitably exhausted polyvalent iso-agglutinating sera. When the birds are closely related, however, this is not always possible, as the corpuscles of certain members of a family may show a very close resemblance. In the course of some earlier experiments, made in order to investigate the hereditary transmission of the characters of the red blood corpuscle, three separate couples of unrelated Plymouth Rock birds were mated, and the cells of parents and offspring in each of the three families examined in detail (Todd, 1930, b ). On reviewing the results obtained and com­paring the behaviour of the corpuscles of the individual members in anyone family, it was seen that the cells of no two chicks appeared to be exactly alike, but that there was always some degree of difference, varying from a close resemblance to a very marked contrast; suggesting that the red cells contain a number of different antigenic units, each of which behaves independently during the process of hereditary transmission.