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» Articles -> Smile Magazine Issue 3 September 2006-> Nosocomial infections with HBV, HCV, and HIV from a dental prospective
Dated : 2006-09-10
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Nosocomial infections with HBV, HCV, and HIV from a dental prospective

  » By: Dr. Ihab Shehadeh

M.D.
Chief Section of Gastroenterology
Director of Endoscopy
Head of Nutrition Dept.
King Hussien Cancer Center

 

Introduction: 

Dentistry a field that has close contact with mucus membranes, saliva and blood of their patients. In patients who are infected with HIV, HBV or HCV the blood and saliva are rich with these organisms. In addition, this is a profession that requires the use of many sharp instruments and tools with the inevitable risk of inadvertent exposure to body fluid of such patients. Therefore, all physicians, nurses and dental technicians should be educated and should be very familiar with the best ways to avoid the exposure and what to do if an incident occurs. In this article I will discuss all three viral infections with special details on hepatitis B infection (HBV) since Jordan is considered a country of high HBV endemicity. I will also detail ways of dealing with exposure incidents.
 
Hepatitis B virus (HBV):
 
Hepatitis B infection is a global public health problem with estimated number of more than 350 million HBV carriers world wide. Roughly over one million die annually from HBV- related liver disease. Despite the presence of an effective vaccine with a universal vaccination program (started 1991) HBV infection continues to be an important cause of morbidity and mortality (1).
 
Epidemiology:

The prevalence varies widely among countries. Regions are divided according to the prevalence into 3 groups. Low prevalence 0.1% -2% (e.g.: USA, Canada, Western Europe), intermediate, 2-5% (e.g. Mediterranean countries, Middle East), and high prevalence, 10-20 % (South East Asia and Africa). Among the Middle East countries: Egypt, Jordan, Oman and Palestine, Yemen and Saudi Arabia have high endemicity; Cyprus, Iraq and UAE have Intermediate endemicity; and of low endemicity Bahrain, Iran and Kuwait (2). The over all estimate of HBV infection in Jordan was around 9.9% in the late 1980’s (3). And in a recent study of a 1000 pregnant women in 2002 the prevalence was still around 11.2% (4).
 
Modes of transmission:
The mode of transmission varies between different geographical areas. Perinatal(mother to infant around the time of birth) is the predominant mode in high prevalence areas, horizontal transmission predominates in intermediate prevalence areas, while intravenous drug use and unprotected sex are the main routes in developed (low prevalence) areas (1). In a study by Toukan et al in 1990, horizontal transmission between young children was the predominant mode of transmission among Jordanian families. Sharing razors, toothbrushes and intimate contact (especially in between siblings playing together and having minor cuts that may be related to the virus transmission) seems to be the main mechanisms behind horizontal transmission.
 
Nosocomial and occupation transmission is the most important mode of transmission that posses a serious risk to dentists and their patients.  HBV infection is the most common blood borne pathogen transmitted in the health care settings (1). Dentists can help transmit the virus among their patients or may contract it them selves from their patients. HBV is capable of surviving outside the body for prolonged periods of time. Subsequently, if medical equipments and tools are not cleaned and then disinfected properly the chances of transmitting the infection can be very significant. And if the dentist and their ancillary services dealing with these equipments do not use appropriate handling methods (universal/standard precautions) they may accidentally get exposed to blood or body fluids of patients infected with these viruses. After a needle stick the risk of developing clinical hepatitis if the blood was both hepatitis B surface antigen (HBsAg)-and HBeAg-positive was 22%-31% the risk of developing serologic evidence of HBV infection was 37%-62%. By comparison, the risk of developing clinical hepatitis from a needle contaminated with HBsAg-positive, HBeAg-negative blood was 1-6%, and the risk of developing serologic evidence of HBV infection, 23%37% (5).
 
Vaccinating health care workers (HCW) and using universal / standard precautions remains the best methods in avoiding HBV transmission to the health care staff. In a study conducted at the Jordan University of Science and Technology Dental Center published 2006, 95% of the staff were vaccinated compared to 87% of nurses (2). The routine use of gloves was very high in both groups but hand washing practices were insufficient in both groups. In contrast to a study in 1990, where only 50% of dental students were vaccinated against HBV (6). Private practice dentists in northern Jordan in a study carried out on 120 centers (91% response rate) showed a staggering 14% only full compliance with all infection control recommendations (7). This shows the dyer need for more education and training.
 
Other modes of transmission include: transfusion related (extremely rare except in transfusion dependant patients), sexual transmission, percutaneous (injectable drug abuse, tattooing, body piercing and acupuncture), and very rarely in organ transplant.
 
Natural history of HBV infection:
 
Three main forms of the infection exist: acute infection, chronic infection and a carrier state.
Acute hepatitis- 70% are subclinical or anicteric while 30% presents with jaundice. After an incubation period of 1 week to 4 months the patient develops a prodrome of constitutional symptoms and then usually within 10 days jaundice develops which lasts between 1-3 months. Serology changes from hepatitis B surface antigen positive to negative and hepatitis B surface antibody (initially IgM and then IgG) become positive indicating cure (8)
Chronic state of HBV infection results from acute infection in an inverse proportion to the age of the patient at the time of contracting HBV. The incidence of chronic infection in Infancy > 90%, between 1-5 years of age 30%, and in immunocompetant adults < 5%.  Chronic infection of HBV is divided into two distinct phases: replicative (Hepatitis B DNA positive +/- hepatitis B e antigen positive) where the virus is actively dividing and damaging liver cells and this can lead to cirrhosis and hepatocellular cancer, the single most common cause of cancer death world-wide, and Non-replicative phase (negative hepatitis B e antigen + negative Hepatitis B DNA) or carrier state. The carrier state is usually not associated with any significant liver damage but patients are at a small risk of the virus being reactivated. They have low infectivity potential but serve as a huge reservoir for the virus to survive and infect others.
Treatment for HBV infection is only indicated for the chronic replicative phase to help arrest the liver damage and decrease the infectivity of these patients. Multiple medications are now available most have limited efficacy in the range of 30% in changing the patient from replicative to non-replicative status.
 
Hepatitis C (HCV):
 
Hepatitis C is single stranded RNA virus that is currently the most common cause of transfusion related hepatitis. There are six different genotypes with geographical variation in prevalence. Genotypes I and IV are believed to be the most prevalent in Jordan (9). The natural history of hepatitis C infection includes acute but sub-clinical hepatitis in most patients and in contrast to HBV infection in adults around 85% of patients with HCV develop chronic infection. Over 15 to 20 years of chronic infection around 15% will progress to cirrhosis and a good portion of those will develop hepatocellular carcinoma or end stage liver disease.
HCV shares with HBV many of the modes of transmission including nosocomial infection (patients to patients or to health care workers), percutaneous, tattooing, and most importantly intravenous drug abuse. On the hand the rate of sexual transmission is much lower (<5%) and Perinatal transmission (<10%). The incidence of HCV in Jordan is in the range of 0.7-1.7% in healthy blood donors, 0.65-6.25% in hospitalized patients (10) and up to 32% in hemodialysis patients (9). The average risk of contracting HCV infection after unintentional needle sticks or sharps exposure is around 1.7% (0-7%) {11}.Unfortunately there is no vaccine against HCV nor are there immunoglobulins for post exposure prophylaxis. Subsequently the use of standard precautions is of utmost importance in preventing nosocomial infections. Treatment in the form Pegylated interferon and Ribavirin came a long way in treating acute and chronic cases of hepatitis C with success rates of 40-80% depending on the genotype being treated.
 
HIV/ AIDS:
 
HIV is the most feared virus when it comes to nosocomial infections. The virus is strongly associated with a very bad social stigma related to the known modes of its transmission (sexual and intravenous drug use) in addition to the over all grave prognosis of those who contract it. The risk of HIV transmission from HIV patients to health care workers was extensively studied and is as follows (12):
 
- From needle sticks the risk is 0.33%.
- From mucus membranes exposure: 0.09%
- From intact skin exposure: 0%.
 
Post-exposure prophylaxis is available for those who qualify but unfortunately no vaccine is available. Please see post-exposure management below.
 
Pre-exposure prophylaxis:
 
Standard precautions previously called universal precautions remain the most important and most effective way of preventing nosocomial infections. These should be used for all patients and any body fluid or instrument that comes in contact with them. The precautions consist of (11):
 
- Wearing gloves: when touching blood, all body fluids (except sweat), and any contaminated item.
- A mask, gown, eye protection, or face shield should be worn during procedures and patient care activity that are likely to generate splashes or sprays of blood, body fluid or secretions.
 
Other methods:
 
- Hard plastic containers for needles and sharps.
- Double gloves for high risk procedures.
- Never recap a needle.
- Vaccination against potential nosocomial infective agents such HBV.
- Proper handling and disinfection of used instruments and tools.
 
Post-exposure management (12) :
 
Taking the correct management of health care workers who are exposed to blood or body fluid from patients with HBV, HCV or HIV is very important in reducing the risk of contracting the virus and in having the best chance of identifying and treating health care workers (HCW) who do contract the virus. It is strongly recommended that big centers or institutions have a written policy of how their employees should be managed post exposure. The following steps should be carried after each incident:
 
Initial actions post-exposure – immediate cleansing of the exposed site with large amount of soap and water the skin injuries. Also antiseptics such as alcohol based solutions can be used for the skin cuts and punctures. Alcohol is virucidal for HBV, HCV and HIV.
 
Documentation of exposure - documenting the site, time and name of patient and HCW. Serological tests for the HCW for HIV, HCV and HBV must be done on both patient and HCW as a base line and for follow up.
 
Definition of exposure - percutaneous vs. mucus membranes (chopped skin, abraded or afflicted with dermatitis).
 
Determining the need for prophylaxis -
 
HIV: based on the risks of transmission and the preference of the HCW. Prophylaxis should be started while awaiting the confirmation of the patient’s HIV status in high risk patients. If a test comes negative then prophylaxis can be discontinued (11).
 
HCV: there is no vaccine against HCV nor are there immunoglobulins for post exposure prophylaxis. HCW who are exposed to body fluids contaminated with HCV should be referred to a specialist in treating this infection.
 
HBV: For vaccinated individuals who have adequate documented antibody response to the vaccine only a booster vaccine in needed. For individuals with uncertain response to the vaccine a booster vaccine and one dose of hepatitis B immunoglobulin is need until a blood test to document the anti-body status of the HCW. For those not vaccinated three doses of the vaccine (at 0, 1 and 6 months) and two doses of hepatitis B immunoglobulin one month apart are needed (1).


 
Conclusion:
 
HBV, HCV, and HIV are important but preventable causes of nosocomial infections that are of special interest to dentists and their staff. Adequate knowledge and practice of standard precautions are lacking in Jordan and are very important for the health and well being of dentist, their staff and their patients. Important efforts are needed to improve on compliance with the infection control methods and pre-exposure prophylaxis. 


References:

1. Eng-Kiong Teo, Anna SF Lok. Epidemiology, transmission, and prevention of hepatitis B virus infection. UpToDate.
2. Qudeimat MA, Farrah RY, Owais. Infection control knowledge and practices among dentists and dental nurses at a Jordanian University Teaching Center. Am J Infect Control. 2006 May;34(4);218-22.
3. Toucan AU et al. The epidemiology of hepatitis B virus among family members in the Middle East. Am J Epidemiol. 1990 Aug; 132(2):220-32.
4. Batayneh N, Bdour S. risk of perinatal transmission of hepatitis B virus in Jordan. Infec Dis Obstet Gynecol. 2002; 10(3): 127-32.
5. Werner BG, Grady GF. Accidental hepatitis-B-surface-antigen-positive inoculations: use of e antigen to estimate infectivity. Ann Intern Med 1982;97:367-9.
 6. Scully C, Bakaeen G, Levers H. Hepatitis B vaccination and infection control practices of Jordanian clinical dental students. J Oral Pathol Med. 1991 Aug; 20(7): 350-1.
7. Al-Omari MA, Al-Dwairi ZN. Compliance with infection control programs in private dental clinics in Jordan. J dent Educ. 2005 Jun; 69(6): 693-8.
8. Schiff ER, Sorrell RS, Maddrey WC. Schiff’s Diseases of the Liver, 1999, 8th edition, Vol. 1
9. Bdour S. hepatitis C virus infection in Jordanian haemodialysis units: serological diagnosis and genotyping. J Med Microbiol. 2002 Aug; 51 (8): 700-4.
10. Quadan A. prevalence of antihepatitis C virus among the hospitalized populations in Jordan. New Microbiol. 2002 Jul; 25 (3): 269-73.
11. David J Weber, William A Rutala, Joseph Eron. Management of healthcare workers exposed to hepatitis B virus or hepatitis C virus. UpToDate.
12. John G Bartlett, David Weber. Management of healthcare workers exposed to HIV. UpToDate.


 

 

 

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