Influenza pandemics can be expected to occur, on average, three to four times each century, when new virus subtypes emerge and are readily transmitted from person to person. The occurrence of influenza pandemics is unpredictable. In the 20th century, the great influenza pandemic of 1918-1919, called the Spanish Flu, caused an estimated 40 to 50 million deaths worldwide.(1) The Spanish Flu was one of the most deadly pandemics in human history.(2) The Asian Flu pandemic of 1957-58 killed 70,000 people in the U.S., and nearly one million worldwide. The pandemic of 1968-69, called the Hong Kong Flu, caused approximately 34,000 deaths and is known as the mildest flu pandemic of the 20th century. Today, annual influenza epidemics cause 36,000 deaths and approximately 226,000 hospitalizations in the U.S.(3) Experts agree that another influenza pandemic is inevitable and possibly imminent.(4)
Influenza outbreaks occur each year due to minor changes in surface proteins of the viruses. These changes allow the newly developed virus to evade the immunity humans have developed following previous infections or from vaccinations. When a major change occurs in either one or both of the viruses' surface proteins, a completely new virus develops, rendering everyone susceptible. If this new virus has a capacity to transmit from one person to another, a pandemic will occur.(5)
The Origins of a Potential Pandemic
Outbreaks of influenza in animals, especially when they occur simultaneously with annual outbreaks in humans, increase the chances of a pandemic due to the merging of animal and human influenza viruses. During the last few years, the world has faced several threats of pandemic potential, making the occurrence of the next pandemic only a matter of time.(6)
In 2004, large parts of Asia experienced unprecedented outbreaks of highly pathogenic Avian influenza caused by the H5N1 virus in poultry. Health officials were swift to tell the public that the H5N1 virus, which is deadly to birds, could not infect humans on an extensive scale and that few, if any, cases of human-to-human transmission of the virus had occurred. Many countries were conscious of the negative economic impact the outbreak could have on the poultry industry, so they quickly reassured the public that eating poultry was safe.
Avian influenza A (H5N1) infections occurred in both poultry and humans, and marked the first time an Avian influenza virus had been found to transmit directly from birds to humans. During this outbreak, 18 people were hospitalized and six died. To control the outbreak, authorities killed about 1.5 million chickens to remove the source of the virus. Scientists determined that the virus spread primarily from birds to humans, although rare person-to-person infection was noted. The virus crossed the species barrier to infect humans with a high rate of mortality. The H5N1 virus has been identified in birds throughout Asia, and in European countries including Romania, Bulgaria, Croatia, and Germany. Of the 16 types of Avian Flu, H5N1 is the one health experts are most concerned about. "H" and "N" refer to proteins on the surface of the virus, while "5" and "1" refer to different forms of the proteins. H5N1 has pandemic potential because it may eventually alter into a form that is contagious in humans.
The survival rate of the H5N1 virus varies widely and depends on temperature, humidity, and other conditions. The virus may survive for weeks in a cool, moist environment. In this way, it can spread from farm to market, from farm to farm, or from farm to a poultry worker's home. In its most lethal form, Avian influenza begins suddenly, causes severe illness, and leads quickly to death in almost all infected birds. This form is referred to as "highly pathogenic Avian influenza," and causes severe epidemics of disease.
Infection Control Measures for Influenza A
According to the Centers for Disease Control and Prevention (CDC), influenza A is transmitted via droplets, which is person-to-person, direct contact, or aerosol (sneezing, coughing, talking, etc.). Therefore, droplet precautions, as well as standard precautions, should be implemented.(7) Due to the high mortality rate that could be linked to a pandemic, the World Health Organization (WHO) recommends that airborne precautions be adhered to when caring for any suspected case of influenza A.(8)
In addition, informed use of Personal Protective Equipment (PPE) is a critical component of any infection control program. Protective garments are essential for any health-care workers caring for any patients with influenza A. Transmission of the influenza A virus may occur through direct or indirect contact with respiratory secretions, such as touching surfaces contaminated with influenza virus and then touching the eyes, nose, or mouth.
Medical and Examination Glove use for Health-care Personnel
Health-care workers should wear gloves if they anticipate hand contact with respiratory secretions, blood, bodily fluids, excretions, or potentially contaminated surfaces. They should put on clean gloves just before touching mucous membranes and/or non-intact skin. Glove should be changed between tasks and procedures on the same patient after contact with material that may contain a high concentration of microorganisms. PPE should be properly removed when leaving the patient's room in order to prevent the spread of microorganisms. When removing gloves, health-care workers should avoid touching the contaminated side of the glove with unprotected hands. When removed properly, both gloves should remain inside out and be dropped directly in an appropriate container. Gloves should never be flicked, snapped, or tossed upon removal. And of course, those in health care should avoid touching their faces, mouths, and noses to prevent the spread of illness.
Protecting Glove Integrity
It is important to make sure that gloves do not come into contact with anything that will cause them to deteriorate or otherwise compromise their protective properties. Gloves should be changed if they come into contact with chemicals or materials that might harm them, such as acids, alkalis, disinfectants, or sterilants. Gloves should never be washed or disinfected with intent to reuse. Petroleum-based products, such as hand lotions, cause latex gloves to degrade. Therefore, if using latex gloves, use water-based products, or check with the manufacturer's guidelines for compatibility guidance.
Age is vital to the integrity of gloves. Gloves should be stored and used in accordance with "first in, first out" practices, which means using the oldest gloves first. Keep gloves in their original packaging until needed, and always follow manufacturers' suggested storage temperatures and guidelines to ensure optimal life of the latex glove. Typically, gloves should be stored in a cool, dry location at 50 to 72 degrees F (10-20 degrees C).
Medical Glove Selection
Glove selection is serious business. The two primary considerations should be barrier protection and allergen content. If a glove does not provide an intact barrier, it is not doing its job. To maximize barrier effectiveness, it is good practice to choose a glove manufacturer that is reliable and experienced to ensure the gloves will be of consistent quality and regularly available. When selecting a medical glove, an important consideration should be the barrier requirement related to the procedure or task at hand. Be aware of the level of exposure risk that the patient care activities will require. Procedures that involve exposure to infectious materials require a glove that provides appropriate barrier protection. The glove should fit well around the wrist. The CDC recommends that gloves fit the user's hand comfortably and not be too loose or too tight. The glove should not rip, tear, or damage easily, and should not roll down unintentionally.(9)
Latex — Latex remains the gold standard for hand barrier protection due to its strength, proven barrier protection, elasticity, fit, feel, comfort, and relatively low cost. With the availability of low-protein, powder-free gloves, many clinicians confidently continue to wear gloves made of latex. Latex gloves are recommended as the first choice for barrier protection in the health-care environment, except for those who are allergic to latex proteins. Latex is available in both surgical and examination gloves.
Latex-Free Gloves — For health-care workers allergic to latex, it is recommended they use a latex-free material of nitrile or neoprene (polychloroprene). In independent testing for barrier properties, studies showed that nitrile, neoprene, and latex gloves are comparable in barrier properties during in-use performance testing.(10)
Nitrile — Nitrile is a petroleum-based, cross-linked film that is extremely strong, with puncture resistance superior to all glove films. Nitrile's elasticity is good, and gloves tend to conform to the shape of the wearer's hands over time. There are no latex proteins in nitrile, so there is no chance of latex allergy. Nitrile is available in examination gloves.
Neoprene — Neoprene is a petroleum-based, cross-linked film that provides barrier protection similar to latex. Neoprene contains no latex proteins, and is available without chemical accelerators, making it a great choice for those with allergies. It is a strong material that resists many chemicals and provides great comfort. Neoprene's elasticity is close to that of latex. It possesses a very high memory that enables the film to retain its original shape, and it is somewhat puncture resistant. Neoprene is available in both surgical and examination gloves.
Polyisoprene — Polyisoprene is a petroleum-based, cross-linked film that provides high strength, elasticity, and comfort. It contains no latex proteins, but contains some curing agents that can cause allergic reactions. Polyisoprene is durable and somewhat puncture resistant, providing good barrier protection. It is more permeable than latex and is recommended as a preferred alternative to latex if nitrile is not available. Polyisoprene is available in surgical gloves.
Polyvinyl Chloride (PVC) — Many hospitals provide a latex-free material called polyvinyl chloride (PVC), commonly referred to as vinyl, as a choice for examination gloves. PVC is a petroleum-based film without latex proteins that is not molecularly cross-linked. Because it lacks cross-linking, the individual molecules of vinyl tend to separate when the film is stretched or flexed. This causes small holes and breaches to form during glove donning and normal use. Studies revealed that 63 percent of vinyl examination gloves permitted leakage of a test virus after normal use, compared with 7 percent of latex gloves.(10) Vinyl is the weakest of the glove films, with poor elasticity, memory, and fit. Because of these inadequate physical properties, vinyl is not an acceptable glove to use during a pandemic event. Vinyl should only be used for low-risk applications that do not involve bodily fluids, blood-borne pathogens, or viruses. Vinyl is available in examination gloves.
Summary
During the past century, the world experienced three global outbreaks, or pandemics, of influenza. The latest appearance and persistence of the emerging influenza virus in birds in Asia and its infection of a limited number of humans with a high mortality rate has raised concern among scientists and public health professionals about the possibility of another pandemic influenza.(1,2)
Influenza A will continue to threaten our health and well-being. As health-care professionals, we need to carefully consider how we can take the necessary steps to ensure that our patients and we are safe from infection. Appropriate PPE, coupled with proper infection control measures, will help optimize protection.
For more information about this module, other Ansell educational programs, or technical questions regarding the suitability or performance of specific gloves, please contact Ansell Healthcare Educational Services at 1-800-952-9916 ext. 7277, or visit Ansell's online educational services at www.ansellhealthcare.com.
References
1. World Health Organization, Epidemic and Pandemic Alert Response. Accessed at: http://www.who.int/csr/disease/influenza/pandemic/en/ on July 10, 2005.
2. World Health Organization, Epidemic and Pandemic Alert Response. Accessed at:
http://www.who.int/csr/disease/influenza/pandemic/en/index.html on July 10, 2005.
3. Reid AH, Taubenberger JK. The origin of the 1918 pandemic influenza virus: A continuing enigma. J Gen Virology Available online at: www.socgenmicrobiol.org.uk/JGVDirect/19302/19302ft.htm. Accessed June 21, 2005.
4. World Health Organization, Epidemic and Pandemic Alert Response. Accessed at:
http://www.who.int/csr/disease/influenza/pandemic/en/ on July 10, 2005.
5. Billings M. The Influenza Pandemic of 1918. June, 1997; modified RDS February, 2005. Accessed at: http://www.stanford.edu/group/virus/uda/ on June 20 2005.
6. World Health Organization, Avian Influenza: Assessing the Pandemic Threat. Accessed at: http://www.who.int/csr/disease/influenza/H5N1-9reduit.pdf on in October, 2005.
7. Centers for Disease Control and Prevention, Infection Control Guidance for the Prevention and Control of Influenza in Acute-Care Facilities. Accessed at: http://www.cdc.gov/flu/professionals/infectioncontrol/healthcarefacilities.htm on November 28, 2005.
8. World Health Organization, Lessons from Past Pandemics. Accessed at: http://www.who.int/csr/disease/influenza/H5N1/9reduit.pdf on August 20, 2005.
9. Centers for Disease Control and Prevention, Infection Control Guidance for the Prevention and Control of Influenza in Acute-Care Facilities. Accessed at: http://www.cdc.gov/flu/professionals/infectioncontrol/healthcarefacilities/htm on June 19, 2005.
10. Korniewicz DM, El-Masri M, Broytes JM, Martin CD, O'Connell KP. Performance of latex and nonlatex medical examination gloves during simulated use. Am J Infect Control 2002; 30(2):133-138.
