March 15, 2010

New Flu, Old Problem
By Larry D. Wright, MD, FACP, AGSF
For The Record
Vol. 22 No. 5 P. 24

Professionals face an exceptional challenge in providing reliable information on addressing the dual influenza threats to older adults.

In 2009, influenza was in the news more than ever before and with a pandemic in progress, 2010 promises a continued focus on the disease. Ironically, the more extensive coverage has been accompanied by both greater public alarm and wider confusion and uncertainty in the community, especially among older adults.

In 1743, well before the so-called germ theory was established as an explanation for spreading illnesses that devastated communities and geographic regions, a contagious disease besieged the citizens of Rome. European newspapers reported the spread of this “contagious influence,” or influenza in Italian.

Almost 200 years passed before scientists isolated the influenza A virus. The original isolate reported in The Lancet in 1933 was a variant of the H1N1 strain that caused the 1918 flu pandemic. A new H1N1 strain of swine flu occurred in 1976, and variants of that virus continue to circulate as one of the seasonal flu agents. This was preceded by the Asian influenza pandemic of the H2N2 virus in 1957.

Much of the current heightened attention is due to the public health concern that started last spring concerning the globally circulating novel H1N1 influenza strain (initially referred to as swine flu) and its unique set of susceptibilities and behavior. Among the most notable components of this flu is the significantly lower risk for infection in older adults, who are typically one of the highest risk cohorts for contracting the more common seasonal flu.

Consequently, healthcare professionals working with elders are faced with a greater challenge in advising patients and caregivers about the current influenza threat. This challenge starts with the fact that the community needs reliable information about two separate types of flu with separate recommendations for prevention and treatment.

Fortunately, healthy older adults are on the lowest priority list to receive the novel H1N1 vaccine. This fact has likely allowed older adults to avoid much of the stress experienced by other groups related to the delay and distribution problems that accompanied the vaccine’s release in October 2009. As always, though, older adults are at the highest risk for acquiring the seasonal flu and should be reminded to get the vaccine every year.

2009 H1N1 Influenza
Formerly referred to as swine flu, the current pandemic influenza has been officially named 2009 H1N1 influenza or novel H1N1 influenza. The term pandemic is used because it has infected large numbers of people globally since it was first recognized during the spring of 2009. As of November 2009, the new strain had been documented in 190 countries and approximately 4,500 deaths had been attributed to it.

The most important problem posed by the novel H1N1 compared with the seasonal flu has been its propensity for infecting younger persons and the dramatically lower risk for older adults. Although a significant number of deaths have resulted from this disease, the U.S. mortality rate thus far has been lower than feared, and most cases of the infection have been relatively mild.

It appears that being born before 1957 is associated with a lower risk for infection with the 2009 H1N1 influenza, suggesting that older adults may have at least some degree of immunity to it as a result of exposure to similar viruses in early life. Nonetheless, the Centers for Disease Control and Prevention (CDC) recommends that older adults receive the H1N1 vaccine once availability has allowed its dissemination to higher risk groups.

As of late October 2009, President Obama declared the 2009 H1N1 pandemic a national emergency, a move that primarily provides support to healthcare organizations by allowing greater flexibility in implementing preventive and therapeutic programs that may be needed.

Types of Influenza
There are three main types of flu: A, B, and C, though influenza type C is of little clinical significance. The most important type has been influenza A, which is subtyped based on its surface glycoprotein components hemagglutinin and neuraminidase (which account for the H and N referenced with different flu strains). Since there are more than 15 kinds of hemagglutinins and nine kinds of neuraminidases, the possible combinations are plentiful. However, since 1977, circulating influenza A strains have been primarily of the H1N1 and H3N2 subtypes.

Influenza is a highly contagious respiratory illness spread from person to person through coughing and sneezing. Those who acquire the flu virus are contagious starting one day before the onset of symptoms and up to five days after becoming sick. The most significant complications of acute influenza include acute bronchitis, bacterial pneumonia, viral pneumonia, ear and sinus infections, dehydration, and worsening of chronic medical diseases. Failure to effectively treat such complications may result in death.

Most individuals with influenza, whether due to the seasonal or the novel H1N1 variety, exhibit a common constellation of symptoms, including mild sore throat, cough, muscle aches, fever, rhinorrhea (clear nasal drainage), weakness, and headache. The presence of fever and cough help healthcare providers distinguish the infection from other viral illnesses, especially when influenza is known to be present in the community.

A higher fever, abrupt onset of symptoms, and greater severity of symptoms also favor an influenza diagnosis. Fever, in particular, is a much less likely feature of the common cold and, when present, typically of lower grade in this and most other common viral illnesses. These differences notwithstanding, the presenting symptom complex of influenza is often more subtle in older adults. In most cases, gastrointestinal symptoms such as nausea, vomiting, and diarrhea suggest a different diagnosis although the novel H1N1 flu has often been accompanied by prominent diarrhea.

Pandemic influenza often differs from the seasonal disease in certain ways. Unlike the seasonal epidemic strains that typically occur during the cold weather months (most often December through March), pandemics may begin and spread during warmer months. Also, the morbidity and mortality tolls vary depending on the virulence of the pandemic strain, and population segments most affected may be much different from the typical seasonal flu pattern. The 1918 influenza pandemic affected healthy, young adults most severely, while the current pandemic appears to preferentially hit young adults and children. Overall, the novel H1N1 influenza seems to cause a milder illness in most cases.

Seasonal Flu and Older Adults
Annually, epidemics of influenza A and B cause substantial morbidity and mortality, disproportionately affecting older adults, very young persons, and those with certain underlying medical conditions. The average number of deaths each year in the United States is 51,000, and more than 500,000 people are hospitalized due to influenza and its complications.

During peak periods of seasonal flu, most hospitalizations occur among patients under the age of 2 or individuals aged 65 and older and among patients with serious chronic medical conditions. More than 90% of influenza-related deaths and two thirds of hospitalizations occur in older patients.

Based on these statistics, this country’s primary public health strategy for reducing the impact of seasonal flu has been prevention, which relies heavily on the annual vaccination of these high-risk groups and those healthcare workers and other caregivers and family members who have close contact with them. Vaccination rates among older adults have increased from 32% to 67% between 1989 and 1997 but remain suboptimal.

The CDC’s Healthy People 2010 initiative sets a goal of having 90% of Americans aged 50 and older receive the seasonal flu vaccine. This goal has not been met in any one state despite wider than ever availability of the vaccine.

Preventing the Spread of Influenza
Whether the problem is seasonal flu or the 2009 H1N1, specific measures and precautions are advisable and extend, for the most part, to preventing the spread of both virus strains. These recommendations include vaccines for each type of flu, personal behaviors to avoid contact with the virus, responses to the onset of flu symptoms, and management of the illness once the diagnosis is made.

Older adults should be advised to get the seasonal flu vaccine every year. Ideally this should be given in October or November but even after an epidemic is well under way, it is not too late. It should be noted that it takes about two weeks for the immunization to become effective. Also, when sufficient supply of 2009 H1N1 vaccine has met the demand of younger age groups, older adults should seriously consider taking that vaccine as well.

While the vaccine is safe for the majority of individuals, it is contraindicated for anyone with a history of allergy to chicken eggs or a severe reaction to a previous flu shot. Also anyone with a history of Guillain-Barré syndrome or who has a febrile illness should not be given the flu vaccine. 

During the flu season, especially if there is a known flu outbreak in the community, one should cough or sneeze into the upper shirt sleeve or cover the mouth and nose with a tissue to avoid spreading respiratory droplets that may carry the virus. Also, washing hands frequently with soap and water before eating and immediately after coughing or sneezing is advisable. Using an alcohol-based hand gel is an acceptable alternative. Everyone should avoid touching the eyes, nose, and mouth, as well as close contact with sick individuals.

Once an individual develops flulike symptoms, it should be reported to a healthcare provider. One of two available antiviral medications, oseltamivir (Tamiflu) or zanamivir (Relenza), may be prescribed, which can help the body fight the seasonal flu and the 2009 H1N1 flu. These are most effective when started early after the onset of symptoms, ideally within the first 48 hours. An individual’s primary care physician or other healthcare provider should determine the advisability of these on a case-by-case basis. The two other available antiviral medications are not advisable for use in older adults due to the risk of certain side effects.

While a person has either type of active influenza, it is best to stay home until five to seven days have passed from the onset of symptoms and there has been no fever higher than 100˚F for at least 24 hours (without the use of acetaminophen or other antipyretic).

The antiviral medications mentioned above can supplement or replace the vaccine if there is a vaccine shortage or if the vaccination is contraindicated and can prevent the spread of the disease during outbreaks in institutions and households. Studies have shown these antivirals to be efficacious when used for prophylaxis in community or family settings where the circulating virus was sensitive to the drug.

Special considerations for containing influenza outbreaks include strategies for preventing spread within residential and healthcare facilities such as hospitals and nursing homes. An important measure should always be to proactively encourage healthcare workers to be vaccinated. Cost-free vaccines offered at convenient times and places can improve coverage among facility staff. During outbreaks, strict observance of contact precautions, visitor limitations, droplet precautions, frequent hand washing, and heightened awareness of all infectious disease policies can be effective in containing spread of the influenza virus.

All professionals working with older adults should try to provide them with the most reliable information, education, and clinical services available for addressing their risks of being affected by influenza. Recognizing that this year may be more challenging than most due to the extra media coverage of the pandemic H1N1 influenza and the seasonal flu, it is imperative that everyone is fully prepared to offer this important service.

— Larry D. Wright, MD, FACP, AGSF, is director of the Schmieding Center for Senior Health and Education and medical director of senior health at Northwest Health System in Arkansas.