Cases of H1N1 are being reported around the world. The 2009 influenza pandemic spread internationally with unprecedented speed. In past pandemics, influenza viruses needed more than six months to spread as widely as the new H1N1 virus that has spread in less than six weeks.

There is widespread H1N1 activity across the United States, National influenza and pneumonia mortality data indicate H1N1 flu activity above epidemic thresholds. Between April and October 2009, more than 20,000 people in the United States had been hospitalized with H1N1. These numbers, which are expected to continue rising, are unprecedented so early in the flu season. Virtually all influenza at this point is H1N1. According to the CDC, the same ages and risk groups at increased risk for seasonal influenza complications are in danger from novel H1N1 influenza complications. These include:

• Children less than 5 years old;
• Persons aged 50 years or older;
• Children and adolescents (age 6 months to 18 years) who are receiving long-term aspirin therapy and who might be at risk for experiencing Reye syndrome after influenza virus infection;
• Pregnant women;
• Adults and children who have chronic pulmonary, cardiovascular, hepatic, hematological, neurologic, neuromuscular, or metabolic disorders;
• Adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV); and
• Residents of nursing homes and other chronic-care facilities.

Globally, teenagers, young adults, and pregnant women account for a significant amount of disease. Rates of hospitalization are highest in very young children. Additionally, pregnant women are ten times more likely to need care in an intensive care unit when compared with the general population. This flu continues to affect mostly younger people. Whereas 90% of deaths during a typical flu season are among people over the age of 65, 90% of deaths in this season are among those under age 65.

For the vast majority of people, H1N1 results in moderate illness. According to the WHO and all available scientific evidence, the severity of the H1N1 influenza pandemic is moderate. This means that:

1. Most people recover from the infection without the need for hospitalization or medical care.
2. National severe illness from influenza A (H1N1) rates closely resemble levels seen during local seasonal influenza periods, although high levels of disease have occurred in some local areas and institutions.

Thus far, hospitals and health care systems in most countries have been able to cope with the numbers of people seeking care, although some facilities and systems have been stressed.

Antivirals

According to laboratory testing, novel H1N1 flu is susceptible to the prescription antiviral drugs oseltamivir and zanamivir (tamiflu and relenza). The CDC and the WHO strongly recommend early treatment with the antiviral drugs, oseltamivir or zanamivir, for patients who meet treatment criteria, even in the absence of a positive laboratory test confirming H1N1 infection. Antiviral drugs should still be considered even 48 hours after symptom onset, particularly for hospitalized patients or people at high risk for influenza-related complications.

Employers should be aware of UPDATED Interim Guidance on Antiviral Recommendations for Patients with Novel Influenza A (H1N1) Virus Infection and Their Close Contacts from CDC. Pre-exposure antiviral treatment should only be used in limited circumstances and in consultation with local medical or public health authorities. Certain persons at ongoing occupational risk for exposure who are also at higher risk for complications of influenza (e.g., health care personnel, public health workers, or first responders who are working in communities with novel H1N1 flu outbreaks) should carefully follow guidelines for appropriate personal protective equipment or consider temporary reassignment.

Vaccines

Vaccines play an important role in national pandemic response plans. Vaccination efforts are designed to help reduce the impact and spread of novel H1N1. Populations targeted for vaccination include those at increased risk of disease or complications, those who are likely to come in contact with novel H1N1, and those who could infect young infants, including:

• Pregnant women,
• People who live with or care for children younger than 6 months of age,
• Health care and emergency services personnel,
• Persons between the ages of 6 months through 24 years of age, and
• People from ages 25 through 64 years who have chronic health disorders or compromised immune systems.

The current circulating virus remains genetically similar to the virus included in the vaccine. As such, available vaccine should be highly effective at preventing illness.

Because H1N1 will only be distributed through public health channels, employers should work with local public health officials to get prioritized employees vaccinated. To that end, employers should be cognizant of a number of H1N1 vaccine issues:

• The federal government will manage distribution of H1N1 vaccine. This vaccine will be distributed through the public health system. As such, it will not be available for purchase in the private market.
• Although the federal government is paying for H1N1 vaccine product, they have not assumed all vaccine administration costs. Employers should work with their health plans to assure coverage of novel H1N1 vaccine administration for all recommended groups.

In any given year, flu vaccine production can be a challenge. The virus can be difficult to grow, sterilized, and distributed in a well-timed process. Despite assurances from manufacturers, H1N1 vaccine production has been slow. For up-to-date information about availability of both novel H1N1 and seasonal vaccine in your states and communities, please refer to the Flu Clinic Locator resource on www.flu.gov.

Leave Policies

People with influenza-like illness should stay home for at least 24 hours after their fever has abated (without the use of fever-reducing medicine). A fever is defined as having a temperature of 100° Fahrenheit or 37.8° Celsius or greater. This is a change from the previous recommendation that ill persons stay home for 7 days after illness onset or until 24 hours after the resolution of symptoms, whichever was longer. CDC recommends this exclusion period regardless of whether or not antiviral medications are used.

This guidance does not apply to health care settings where the exclusion period continues to be for 7 days from symptom onset or until 24 hours after the resolution of symptoms, whichever is longer.

Travel Warnings

WHO does not recommend countries implement travel restrictions. Global travel is commonplace; large numbers of people move around the world for business and leisure. Limiting travel and imposing travel restrictions would have very little effect on stopping the virus from spreading. It would also be highly disruptive to the global community.