Singapore has given the green light for several new vaccines specifically designed for children. Among these are vaccines for two potentially devastating conditions - gastroenteritis and pneumonia.

'Vaccines are the most effective and most potent of public health measures. Thousands of children everywhere stand to benefit from each new vaccine development,' says Dr Nitin Shah, consultant paediatrician at the PD Hinduja Hospital in Mumbai, India.

One new vaccine which will soon be marketed here is Merck's Rotateq, which received approval from the Health Sciences Authority just two months ago. Rotateq is a 'live' viral vaccine that is suitable for very young children, especially infants.

'Rotavirus, or gastroenteritis, can cause severe diarrhoea, vomiting and fever in young children. It is the second biggest cause of death in children in many parts of the world,' says Dr Shah.

In fact, almost every child will have suffered one bout of rotavirus infection by the time they reach five years of age. The spectrum of illness, however, can range wildly from mild to severe. In serious cases, gastroenteritis can lead to dehydration, shock and even death.

'The infection can begin rather abruptly. It is not necessarily governed by hygiene, so children from developed countries are also at risk,' explains Dr Shah.

According to him, the most severe cases tend to be very young children between the ages of six months and two years.

Rotateq, an oral vaccine in liquid form, gives immunity from four strains of the virus and is administered in three separate doses, usually to babies between the ages of six and 32 weeks.

The vaccine, which has an efficacy rate of up to 98 per cent, was studied in a trial that includes nearly 70,000 infants, making it one of the largest pre-licensure trials in vaccine history.

Another rotavirus vaccine that has been approved is GlaxoSmithKline's Rotarix, which was launched in Mexico in 2005, and has since been granted licences in a large number of countries worldwide, including Singapore. Rotarix is already available at most GP clinics here.

An equally important development in childhood vaccination is Wyeth's Prevenar, which acts against pneumococcal disease - a group of illnesses caused by the bacterium streptococcus pneumoniae, also known as pneumococcus.

This bacterial pathogen affects both adults and children, but can be especially dangerous for the latter.

Infants from birth to 24 months are at high risk due to their low levels of circulating pneumococcal antibodies. Since as many as 60 per cent of all preschool children are carriers of pneumococcus, children who attend day-care centres are also much more likely to become infected due to their increased exposure to the bacteria.

Pneumococcus is commonly found in the nose and throat, and can be transmitted through airborne particles, such as those in sneezes or coughs.

'This disease is a growing threat to children's health worldwide, and far too many children die from it every year,' says Dr Shah.

According to him, the bacteria can cause meningitis, a serious and often fatal brain infection; pneumonia, and otitis media, an ear infection that can lead to loss of hearing.

Currently, there are about 90 different pneumococcal strains but out of these, only a small number is responsible for the majority of all invasive pneumonia cases among infants and young children. In Singapore, the four most common strains are 6B, 14, 19F and 23F.

Prevenar covers 86.6 per cent of the serogroups in Singapore known to cause invasive pneumococcal illnesses.

'In a major US trial that involved more than 35,000 children, Prevenar proved to be more than 97 per cent effective in immunised children,' says Dr Shah.

The vaccine is injected into the body to stimulate the normal immune system to produce antibodies that are directed against the bacteria. Depending on the age of the child, he or she may require between one and four doses. Each dose costs about $180.

'Vaccination with Prevenar can be given to infants as young as six weeks, and to children as old as nine years,' explains Dr Shah.

Asked if it is possible for a child to have one too many vaccinations, Dr Shah says: 'That's not at all a problem. Even a newborn's immune system is tuned to handle thousands of organisms at any one time. A few vaccines - that's nothing at all.'

He strongly advises all parents to stay vigilant where their children's vaccinations are concerned.