BACKGROUND TO VIRUSES AND THE DENTAL PROFESSION

The earliest days of viruses are difficult to date but evidence suggests they have been evolving for 125,000 years

In 1918 the swine flu pandemic, caused by the Influenza virus, infected 500 million people and over 17 million perished.

In about 1980 the identification of the Hepadnavirus group causing Hepatitis and especially the Hepatitis B virus, became relevant to dentistry which was followed, in 1981, by a Lentivirus that causes AIDS. These two viruses are both transmitted by bodily fluids -blood etc.- entering the body tissues of another person.

These required a major change for the Dental Profession to prevent the transmission of these viruses from patient to patient, patient to staff or staff to patient.

The assumption made was that all patients were potential carriers so all instruments as well as being thoroughly cleaned were then sterilised by high temperature steam under pressure [autoclaving] and any instruments that could not be sterilised in this way became single use only. The wearing masks and disposable gloves became the norm {PPE}. A vaccine for Hepatitis B was developed and vaccination with proof of antibody status has become a mandatory requirement for dental personnel. No vaccine has been found for the AIDS virus.

Correct procedures in cross-infection control reduce the transmission risk of these viruses to an exceedingly low level. These two viruses however were both transmitted by bodily fluids entering the body tissues of another person.

In 2003, SARS – Severe Acute Respiratory Syndrome became the new virus {SARS –CoV} in town. Transmission of SARS-CoV is different from the previous 2 in that it is primarily transmitted person to person by airborne droplets or fomites. It appears to have occurred mainly during the second week of illness, which corresponds to the peak of virus excretion in respiratory secretions and stool, and when cases with severe disease start to deteriorate clinically. Most cases of human-to-human transmission occurred in the health care setting, in the absence of adequate infection control precautions. Implementation of appropriate infection control practices brought the global outbreak to an end but still caused an epidemic which affected 26 countries and resulted in more than 8000 cases with almost 800 deaths. No vaccine has been found.

In 2012 the Middle East Respiratory Syndrome, MERS, was caused by the MERS CoV virus and human to human transmission was through close contact but 35% of know sufferers perished {over 650 deaths.} No vaccine has been found.

In 2019 /2020 SARS CoV-2 was identified and quickly became a pandemic. The SARS virus -causing the Covid-19 infection- is spread in small airborne droplets of saliva coughed or sneezed into the air by an infected person. Anyone breathing these in are at risk of developing the infection. Also this airborne transmission can occur in specific circumstances and settings in which procedures or support treatments that generate aerosols are performed and if someone else breathes in the droplets. It’s these aerosol generating procedures – caused by rotating drills and water and air sprays that are of extreme importance in relation to the safe provision of modern dentistry. Development of a vaccine is being attempted.