Because viral diseases are hard to treat, prevention is the most effective approach. Prevention works by breaking the chain of transmission, so that virus particles never reach a new host. The method used depends on how the virus spreads.Airborne viruses (influenza, COVID-19, colds):
• covering coughs and sneezes, and disposing of tissues
• face masks, good ventilation and staying at home when illContact and fomites:
• frequent hand washing with soap, or alcohol hand gel
• disinfecting surfaces; gloves and aprons in hospitalsViruses in body fluids (HIV, hepatitis B):
• using condoms
• not sharing needles; needle exchange programmes for drug users
• screening donated blood; heat-treating blood products
• antiviral treatment of HIV-positive mothers to reduce vertical transmission, and pre-exposure prophylaxis (PrEP)Faecal-oral viruses (norovirus, polio):
• clean drinking water and good sanitation
• careful food hygieneVector-borne viruses (dengue, Zika):
• insecticide-treated bed nets and repellents
• removing standing water where mosquitoes breedVaccination gives individuals immunity before they meet the virus, and is often the most powerful preventive measure of all.A good answer to an exam question links the prevention method to the route of transmission. For example, condoms prevent HIV spreading because they stop the exchange of body fluids during sex, whereas hand washing would have little effect on HIV.
• covering coughs and sneezes, and disposing of tissues
• face masks, good ventilation and staying at home when illContact and fomites:
• frequent hand washing with soap, or alcohol hand gel
• disinfecting surfaces; gloves and aprons in hospitalsViruses in body fluids (HIV, hepatitis B):
• using condoms
• not sharing needles; needle exchange programmes for drug users
• screening donated blood; heat-treating blood products
• antiviral treatment of HIV-positive mothers to reduce vertical transmission, and pre-exposure prophylaxis (PrEP)Faecal-oral viruses (norovirus, polio):
• clean drinking water and good sanitation
• careful food hygieneVector-borne viruses (dengue, Zika):
• insecticide-treated bed nets and repellents
• removing standing water where mosquitoes breedVaccination gives individuals immunity before they meet the virus, and is often the most powerful preventive measure of all.A good answer to an exam question links the prevention method to the route of transmission. For example, condoms prevent HIV spreading because they stop the exchange of body fluids during sex, whereas hand washing would have little effect on HIV.