Many injections given in the developing world are unsafe, a British Medical Journal study finds.
Needles can be kept in unhygenic conditions
World Health Organization researchers found up to 75% of injections were given with re-used, unsterilised equipment, increasing infection risk.
Re-use was highest in South East Asia, the Middle East and the Western Pacific.
The researchers are calling for greater efforts to hammer home the importance of good hygiene.
They also say single use injection devices must be made more easily accessible.
It is thought the use of unsafe injections is a major cause of the spread of viruses which cause a range of serious diseases, including hepatitis B and C, HIV, absceses, septicaemia, malaria and haemorrhagic fevers.
The researchers found that overall almost one in three injections in developing and transitional countries were administered using re-used and unsterilised equipment.
Too many jabs
They also found too many injections were routinely administered, with each person in these countries receiving an average of 3.4 injections per year.
This is partly due to public demand, the researchers accept, but also stress that health workers seem too keen to offer injections when other, potentially safer methods are available.
They put this down to misconceptions that patients prefer injections, and that they are the best way to deliver treatment.
Lead researcher Dr Yvan Hutin told BBC News Online: "A common scenario is that a patient goes to a doctor with fever or a body pain, and the doctor mixes up a number of antibiotics and vitamins and administers them as an injection when an oral preparation or no treatment at all would be the best option."
The researchers found that injection practices are safer in sub-Saharan Africa than in other parts of the developing world, such as the Middle East and South Asia.
They believe this may be due to an increased awareness of the risk of HIV transmission in sub-Saharan Africa, which has been particularly hard hit by the virus.
Research has shown that the proportion of the population aware of the potential risk of HIV infection through unsafe injections was 24% in Pakistan in 1998, 19% in India in 1999, but 52% in Burkina Faso in 2001.
Writing in the BMJ, the researchers say: "An urgent need exists to use injections safely and appropriately, to prevent healthcare associated infections with HIV and other bloodborne pathogens."