Once the immune system has been primed (by the vaccine) to recognise the disease, future infections will be dealt with swiftly by killing the infectious agent (bacteria or virus), before it has a chance to spread and make the person ill.
There are some diseases for which immunisation is not (currently) possible, but many vaccines exist.
Can you name six infectious diseases for which vaccines have been developed?
There are many types of vaccine. Sometimes the same disease can have different types of vaccine available. For interested members, further information on the four main types is given below:
In an attenuated vaccine, live pathogens (virus or bacteria) with very low virulence are given. They will reproduce, but very slowly. Effectively, they create a very low grade chronic infection, one that doesn’t cause illness.
These viruses / bacteria are grown under less-than-ideal conditions, and their offspring are selected for weakness, rather as dog breeders might select for a shiny coat. The weakened generations are used to produce the vaccine.
Since they do reproduce and continue to provoke the immune system after the initial vaccination, boosters are required less often.
Attenuated vaccines are sometimes called "Live Vaccines"
An inactivated vaccine is made from pathogens which are grown in a culture and then killed with for example heat or formaldehyde.
The pathogens cannot replicate, but the proteins on their coat are intact enough to be recognised and remembered by the immune system and evoke a response.
Examples of inactivated vaccines:
Whooping Cough. Influenza. Typhoid. Cholera. Polio.
These consist purely of proteins obtained from the coat (capsid) of a virus. These proteins assemble themselves into particles that resemble the virus from which they were derived.
They are not infectious as there is no DNA/RNA in them.
Examples of virus-like particle vaccines
Human papillomavirus. Hepatitis B.
These consist of a single specific protein from a virus or bacteria (such as a bacterial toxin). E.g. the vaccination against tetanus does not use the bacterium, but a toxin produced by it.
If an individual is immune to an infectious disease, they don’t have to worry about it. If most of the population is immune, the pathogen has nowhere to live, and will die out. Vaccination programmes have eradicated smallpox, and the World Health Organisation is trying to do the same with polio.
Vaccination and dentistry All members of the dental team should, at a minimum, be vaccinated against TB and hepatitis B. This is for their own protection, and also to ensure they don’t become carriers, and potentially pass the disease on the patients and other staff.
Hepatitis B: fitness for work
Carrier testing
Dental surgery staff should not be an "infection hazard" - that is, they should not be carrying the Hep B virus. The first test for new staff is to see whether they are a carrier.
This is done with a Hepatitis B Surface Antigen test. If they are Antigen Positive, they might be carriers. Further tests on the amount of virus in their blood will determine whether this is the case. If they are carriers, they must not work directly with patients or instruments (i.e. undertake "exposure-prone procedures").
Immunity testing
However, let's hope they are not carriers, and they pass the test.
The next test is to check their immunity to Hepatitis B.
This is done with a Hepatitis B Surface Antibody test. If the antibody levels are high, they are immune, and can work unrestricted. They will be advised (usually by the unit that arranged the testing) how often they should have a booster.
Advice on booster necessity and frequency varies. There is some evidence (references below) that even with no booster, previously immunised people can remain immune, despite their measured antibody levels being very low. However, for health professionals, one further booster at 5 years is the most common recommendation (with none after that).
It is important to seek individual advice, as some other illnesses (causing for example immunosuppression) may vary your immunisation needs.
Wainwright RB, Bulkow LR, Parkinson AJ, et al. Protection provided by hepatitis B vaccine in a Yupik Eskimo population: results of a 10 year study. J Infect Dis. 1997;175:674-677.
Shih HH, Chang MH, Hsu HY, Lee PI, Ni YH, Chen DS. Long term immune response of universal hepatitis B vaccination in infancy: a community-based study in Taiwan. Pediatr Infect Dis J. 1999;18:427-432.
If they have low (or zero) antibodies they will be advised on whether they simply need a booster, or an entire course of immunisation.
Failed immunity
The Hepatitis B vaccination does not work on everyone. If a healthy employee fails to become immune, a decision has to be made:
A) Should they be prevented from exposure-prone procedures, because of the risk to themselves?
B) Should they be allowed to work normally?
Most organisations go for (B), with the proviso that they are tested every three months to ensure they haven't become infected. However, this depends on local guidelines and policies.
Monitoring (and audit) of immune status
It is essential that details of staff immunity are recorded, with original proof of vaccination certificates, and blood test results when appropriate.
There must be a mechanism that reminds staff when they need a booster, and ensures that this gets done.
This log forms part of a practice's Clinical Governance Portfolio. It can be paper based, or computerised.
The log is a confidential practice record: staff confidentiality must be ensured.
Key Points
Please take a moment to review these points, reflect on their significance, and consider how they apply to your own experiences.
Tick to confirm (optional):
Vaccination primes the immune system to recognise and swiftly eliminate infectious agents, preventing illness.
Common vaccines target diseases like Tetanus, TB, COVID-19, Hepatitis B, Polio, and Influenza.
No vaccines currently exist for diseases such as HIV and Hepatitis C, though research is ongoing.
Vaccine types include attenuated (live), inactivated, virus-like particle, and subunit vaccines.
Dental professionals should be vaccinated against TB and Hepatitis B for personal and patient safety.
Hepatitis B carrier and immunity testing are essential for dental staff, with records maintained as part of clinical governance.
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