MRC National Institute for Medical Research, London

After such excellent efforts, the participants deserve some comments on the way the essays were written generally and our impression of how the specific essays could have been written.

The overall standard of writing of the finalists was high and once again significantly higher than the previous year; most entrants made great efforts to develop a logical narrative with a clear focus.

In adjudicating a competition of this kind, the judges sometimes have to choose between entries with a high quality of information or a particularly attractive style of writing. Entries that were properly referenced clearly gave a good impression, but most authors had managed this very well. (Some bibliographies indicated prodigious reading that extended to 20 or more references!)

The opening paragraph

Perhaps the single biggest challenge lies with the opening paragraph. In an essay of this length, the opening sentence should convey at least a partial summation of your thoughts about the title. In the case of the AIDS and TB titles, the subject was generally introduced in a rather roundabout way, starting with a description of the disease or the organism that added little to the main thrust of the essay. Importantly, some sentences that appeared later in essays would have been appropriate starting points.

Missing information

A few otherwise good efforts were brought down by the absence of certain crucial pieces of information, such as multiple drug resistance in TB.

A valuable experience

All those who participated have picked up important skills that they may develop further in the future. We hope entrants thought the effort was worthwhile and feel that they learnt from the experience.

Forty years ago we thought we had nothing more to fear from TB. The drugs and vaccines available now may not be adequate for the growing problem.

Almost every one knew that TB is very common in the world but fairly rare in Europe. Many essayists did not appreciate the numbers now being recorded are very low compared with 100 years ago, and that it is easy to over-estimate the seriousness of the resurgence. To put this in context, one in five Victorians died of TB; the disappearance of the disease is largely attributable to improved public health and nutrition although the BCG and other drugs meant the disease could be eradicated in some regions. It's also worth pointing out that the BCG vaccine is not life-saving; its role is preventive and it would have no affect on an infected patient.

Many knew about drug resistant strains but seemed unaware that it's necessary to use a combination of two drugs to cure the infection without a drug resistant strain being selected. DOTS (the internationally-recommended TB control strategy) is intended to ensure compliance.

Most knew that TB cases arrived with immigrants from areas where public health measures were not very effective, however there were few topical references about sources (e.g. spread in prisons, use of single drug therapy, existence of counterfeit drugs).

The best essays acknowledged that AIDS activates dormant cases and may increase the chances of spreading to others. However, it would be wrong to suppose that the appearance of HIV was the entire cause of the resurgence of TB.

HIV became a serious danger rather suddenly and we have a long way to go before it ceases to be a threat.

Most people knew that HIV is dangerous because it destroys the immune system, so that victims eventually succumb to opportunistic infections and tumours, and everyone seemed to know how it was spread. The key danger, not so clearly expressed, was that asymptomatic victims may spread the virus and the latent period may be very long.

Many knew that combinations of anti-retroviral drugs can prevent development of full-blown AIDS for a very long time. This could bring the epidemic under control in principle but is not realistic in Africa where the cost, even with philanthropic help, is probably prohibitive.

These essays were slightly disappointing chiefly because they did not really have any interesting insights into the second part of the title. There are many reasons why vaccines have not yet been successful (of which error prone transcription of the virus is the most important). Many essays neglected this feature of the virus. One essayist had a novel idea, that the stock of infected blood should be replaced. In fact there has been interest in bone marrow transplantation after a procedure that destroys the natural blood cell progenitors, but has not caught on. Making a vaccine to treat already-infected patients is not realistic, as a vaccine would not eliminate copies in the genome. Nobody mentioned the idea that if the virus was not passed on, it would disappear with this generation of victims.

Is it particular foods that make people fat or just too much.

Entrants partially recognised that there was no absolute distinction between 'junk food' and 'healthy food' and that the phrase 'junk food' was largely a disparaging term for what's 'uncool' at a nutritional or an aesthetic level. However, in the interests of science a better definition of healthy diet would have made the essays work. People knew that diet should be 'balanced' but what practical guidelines does one follow?

Another important dimension of healthy eating is 'how much'. Relatively sedentary people might need 2000 calories a day but people doing heavy physical exertion might need twice that. Clearly the wrong combination is unhealthy. All the information we have suggests that people who eat the least (above a certain threshold) live the longest and healthiest lives.

This essay could have addressed particular health risks that might be attributed to 'junk food'. These include:

• a high energy density that doesn't easily quench the appetite so that people put on excessive weight
• too much salt
• 'unnatural' chemicals as colorants or tastes
• trans fatty acids
• deficiencies in micronutrients (the hardest to substantiate)

Scientists often talk excitedly about the impact of forthcoming discoveries; what aspects of present day life, if any, would you like to see transformed by biomedical research?

The number of responses to this title was disappointing. The idea was for it to be an opportunity for imagination and lateral thinking which could have taken many forms, such as:

• a cure for the common cold
• drugs to improve memory and concentration
• better methods for regenerating damaged tissues
• drugs to delay the menopause so that women could have babies in their 40s if they wanted to have a career first
• a generic cure for cancer based on a drug that prevented any cell division getting out of control
• methods for eliminating allergies

The two entries received were brave and quite imaginative although with some imperfections. One essayist wished there were ways of improving the chances of accident victims. Much of the essay was about averting the risks associated with blood transfusion, the need for protein factors that stimulate blood regeneration (erythropoietin) and gadgets for bloodless surgery. Another response was an uninhibited exploration of ways of treating genetic diseases by si-RNA.

Both entries were very interesting but probably fell by the wayside because the authors didn’t quite convey how life would be revolutionised. To do that successfully requires us to first estimate the problem, and it's here that imagination is required.

The idea of selecting an embryo, conceived by IVF, that will become a child that can donate cord blood or bone marrow for an older sibling suffering from a genetic disease has created a difficult moral dilemma.

This essay topic required a description of exactly what is involved in this intervention: deliberate selection of an IVF embryo that does not carry the same genetic disease as an older sibling so that it can donate tissue (e.g. bone marrow or cord blood) to treat an elder sibling.

The title had two aspects, whether it was 'humane' or whether it was 'proper'. If a condition can be cured, one might suppose it is a humane step to do it, whatever the cost. This is a case where 'humane' can conflict with 'proper'. The ethical problem is that the second child could never give 'informed consent' before hand. Arguably this is a trivial matter if cord blood cells are to be used but a different matter if bone marrow donation is required.

Two important British precedents are relevant to this essay. One is the Hashmi's who were permitted to conceive a second child by IVF after pre-natal diagnosis. The child could be a cord blood donor for the older sibling who had thallasaemia. This was permitted, as the second child would clearly benefit from the arrangement, and the embryo selection process would ensure the child was free of thallasaemia. Another important story was about Charlie Whittaker whose parents were refused help with curing Charlie of Blackfan-Diamond syndrome (a fatal anaemia). The grounds were that the second child had nothing to gain from the intervention (no disease was being screened for, as the sibling was a new mutation) and was at risk of all the things that IVF babies might suffer.

The essay competition winner negotiated the tricky ethical arguments skillfully, conveying the context of these interventions, including the technology and the role of the regulatory authorities, in an interesting and accurate manner. Some matters were left unsaid but it was a very good effort. Other essays, with admirable forthrightness, were sceptical about the entire idea of saviour siblings.