H1N1 Update

· Influenza illness, including illness associated with the novel influenza A H1N1 virus is ongoing in the United States.

· There are localized outbreaks of novel H1N1 activity ongoing in several states.

· The states that have reported the most novel H1N1 activity are Arizona, California, Illinois, New York, Texas, Washington state and Wisconsin.

· On May 21, 2009 CDC reported a total of 5,764 probable and confirmed cases of novel H1N1 infection with 9 deaths.

· The most recent reported death occurred in a 22-year-old in Utah.

· This number is thought to represent a small proportion of the total number of people who have been infected with the novel H1N1 virus.

o This is an underestimate because

§ Many people ill with influenza-like symptoms do not seek medical care

§ Many who do seek medical care are not tested for influenza

· It’s uncertain at this time how severe this novel H1N1 outbreak will be in terms of how many people infected have severe complications or death related to novel H1N1 infection.

· We are still learning about the severity and other epidemiological characteristics of the novel H1N1 virus.

· So far, the largest number of novel H1N1 confirmed and probable cases (more than 60% of cases) have been in people between the ages of 5 years and 24 years old.

· However, nearly 40% of hospitalizations have occurred in people between the ages of 19 and 49 years of age. And about 18% of hospitalized patients have been between the ages of 10 and 18 years old. Only 13% of hospitalizations have occurred in people 50 years and older.

· Pregnancy and other previously recognized medical conditions from seasonal influenza appear to be associated with increased risk of complications from this novel H1N1 as well.

· Seventy-one percent (71%) of hospitalized patients have had underlying chronic medical conditions.

· Reported deaths have occurred in people ranging in age from 22 months old to 57 years old.

· There are few cases and no deaths in people older than 65 years, which is unusual when compared with seasonal flu.

· There is not enough information at this time to predict how severe this novel H1N1 outbreak will be in terms of illness and death or how it will compare with seasonal influenza.

MMWR

· The May 22 issue of the MMWR will contain an article entitled “Cross-reactive Serum Antibody Response to the Novel Influenza A (H1N1) Virus After Vaccination with Seasonal Influenza Vaccine.”

· This MMWR article provides details of a serology study of samples from children, younger adults and older adults vaccinated with recent seasonal influenza vaccines to try to determine whether seasonal vaccines offered any immune benefits against novel H1N1 virus.

· “Serology” is the study of blood serum to identify antibodies in the serum. Serum is what is left when red and white blood cells are removed from blood. The presence of antibodies in serum can indicate immune protection against a certain infectious agent.

o CDC conducted this study using stored sera collected from children in age groups ranging from 6 months to 9 years of age and adults 18 to 64 years old or adults older than 60 years vaccinated with the seasonal influenza vaccines developed for influenza seasons from 2005 to 2008.

· The results presented in this study found that the seasonal influenza vaccine provides little or no immune benefit against the novel H1N1 flu virus.

· Specifically, the study found that:

o Children have no existing antibody immunity to the novel H1N1 flu virus and did not develop antibody after vaccination with seasonal vaccine.

o Some younger adults had a low level of cross-reactive antibody against the novel H1N1 flu virus prior to vaccination with seasonal vaccine. There was a small increase in the level of cross-reactive antibodies after vaccination with seasonal influenza vaccine.

o About one-third of adults older than 60 years of age had cross-reactive antibody against this novel H1N1 virus prior to vaccination with seasonal vaccine. There was no increase in the level of these cross-reactive antibodies in older people after vaccination with seasonal influenza vaccine.

· These results suggest that some adults may have some degree of preexisting cross-reactive antibody to the novel H1N1 flu virus, especially adults older than 60.

· It is unknown how much, if any, protection may be afforded against the novel influenza A (H1N1) by existing antibody.

o A possible explanation to this preexisting antibody in adults is that they may have had previous exposure, either through infection or vaccination to an influenza A H1N1 virus that was more closely related to the novel H1N1 flu virus than are contemporary seasonal influenza A (H1N1) strains.

· CDC believes, based on this data, that seasonal influenza vaccine is unlikely to provide any meaningful protection against novel influenza A (H1N1) virus.

· Vaccination with seasonal vaccine is still recommended to protect against the seasonal influenza viruses in the vaccine.

· The MMWR report is available at http://www.cdc.gov/mmwr/

Vaccine

· Vaccines are a very important tool for the prevention of influenza, including novel influenza that may become pandemic.

· CDC has isolated the novel H1N1 flu virus and is working to make a candidate vaccine virus that can be provided to industry so that manufacturers can scale up for production of a vaccine, if necessary.

· CDC is hopeful that we will have vaccine viruses to send to manufacturers by the end of May.

· This is within original timelines sent out by CDC.

· There are many steps involved with producing a vaccine, and we are committed to working with the NIH, FDA, BARDA, WHO and the manufacturers of influenza vaccines through this process.

· If things go well, and a decision is made to seek full scale vaccine production, it will be several months until the vaccine will be available.

· So a vaccine is an important tool for the future.

Seasonal Flu Vaccine. Production of the seasonal flu vaccine for next season is nearly complete and will be completed. Seasonal flu is responsible for causing an estimated 36,000 flu-related deaths and 200,000 flu-related hospitalizations in the U.S. each year. Seasonal flu vaccine is always a public health priority.

Stay Home If You Are Sick

Do not travel if you are sick

· To help control the spread of novel H1N1 flu, those who are sick with flu-like symptoms should stay at home except to seek medical care or for other necessary reasons.

· The symptoms of this new H1N1 flu virus in people are similar to the symptoms of seasonal flu and include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue. A significant number of people who have been infected with this virus also have reported diarrhea and vomiting.  

· Staying at home means that you should not leave your home unless you need to go to the doctor. This means avoiding normal activities, including work, school, travel, shopping, social events, and public gatherings.

· If you are sick, CDC recommends that you stay home for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer. This is to keep from spreading the virus to other people.

· Resting at home will also help you feel better sooner.

· Even if you start to feel better during this period, it is important that you stay home for the recommended time except to seek medical care or if needed. You should not travel, go to work or school, or run errands.

· If people with flu-like illness must leave their home (for example, to seek medical care or other necessities) they should cover their nose and mouth when coughing or sneezing. A surgical loose-fitting mask can be helpful for people who have them, but a tissue or other covering is appropriate as well.

· If you get sick with flu-like symptoms and have a trip scheduled, you should not travel until 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer.

· If you get sick during a trip, you should stay in your hotel room for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer (except to seek medical care or other necessities).

· Have you ever worried that you may become sick because you had to sit close to someone who was sick on a plane, in the office, or at school? Remember that if you were healthy, you would want sick people to stay at home instead of traveling and risking the health of others.

· If you are sick, think about your fellow passengers before you travel. Do your part -- stay home, recover, and keep others well.

· For more information about healthy and safe travel visit www.cdc.gov/travel or call 1-800-CDC-INFO

There is no vaccine yet and antiviral drugs may be difficult to get when traveling.

· There is not yet a vaccine for novel H1N1 flu. Scientists are working hard to develop one.

· Antiviral drugs are prescription medicines (pills, liquid or an inhaler) that can work against flu viruses, including novel H1N1 flu.

· Do not assume that antiviral drugs will be easy to get if you are traveling.

· If you are sick, take steps to keep from spreading the virus to other people:

· Stay home for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer.

· If you get sick during a trip, you should stay in your hotel room for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer.

· If you must leave your home or hotel room (for example, to seek medical care or other necessities), cover your nose and mouth when coughing or sneezing. A surgical loose-fitting mask can be helpful for persons who have access to these, but a tissue or other covering is appropriate as well.

· Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

· The best way to protect yourself from novel H1N1 flu is to take everyday steps to reduce the spread of the virus. These steps are:

· Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective.

· Do not touch your eyes, nose or mouth. Germs spread this way.

· Avoid close contact with sick people.

· For more information about healthy and safe travel visit www.cdc.gov/travel or call 1-800-CDC-INFO

School Closures

· At this time, schools across the country continue to close as a result of novel H1N1 flu activity based on local considerations.

· We know that children are susceptible to novel H1N1 flu, and schools or childcare facilities may act as a point of spread.

· As we know from seasonal flu, schools are a challenge. Aside from closing schools for an extended period of time in coordination with other means to reduce spread in a community, there is no approach that will completely stop or prevent transmission of flu in a school setting.

· There is a need for localized responses in schools, and when absentee rates are increasing in students and staff due to novel H1N1 flu illness, it is appropriate to close schools if they are not able to function.

· On May 5, CDC issued updated guidance for schools impacted by novel H1N1 flu infections. This guidance attempts to strike a balance between measures that may have an effect on slowing transmission and those that create other problems (such as disrupting education and sending kids to malls or other social gathering spots where they’d still be susceptible.)

· In the updated school guidance, CDC recommends that parents and guardians should monitor their school-aged children, and faculty and staff should self-monitor every morning for symptoms of flu-like illness.

· CDC understands that parents are concerned about how to protect their children from novel H1N1 flu and other infectious diseases.

· As much as we wish there was, there is no approach that will guarantee protection from infectious diseases spread by flu viruses.

· This is why CDC is working to develop a vaccine for the novel H1N1 flu virus. Vaccines are not 100 percent effective, but they provide the best protection against viruses, such as flu.

· Antiviral medications can also be used to treat flu illness, and in some cases, to prevent flu infection. Use of antiviral medications for prevention may be particularly important for people at high risk of flu complications who have had a close exposure to someone with novel H1N1 flu

· Even if a school is closed for an extended period of time, both children and adults are still susceptible to flu if they have interactions with other people, some of whom may be shedding flu viruses even though they don’t have symptoms.

· The largest number of novel H1N1 confirmed and probable cases are occurring in people from the ages of 5 to 24, so many of them are school-aged children.

· Students, faculty, and staff who have flu-like illness should stay home for 7 days after symptoms have started or at least 24 hours after symptoms resolve, whichever is longer, seeking medical care if symptoms are severe.

· Students, faculty and staff who appear to have flu-like illness or become ill during the school day should be isolated promptly in a room separate from other students and sent home.

· Any dismissal based on local considerations must be done while working closely with the local or state health departments.

· Schools and childcare facilities do not need to do extra cleaning (such as washing walls) before children can return.

· Schools can help teach students and staff how to reduce the spread of novel H1N1 flu through hand hygiene and cough etiquette.

· Washing hands or use of alcohol-based gels in schools or at home can offer protection.

· People at high risk for flu associated complications who have had close contact with someone sick with flu should consider talking to their health care provider about influenza antiviral medications.

Seasonal Influenza Context

Flu seasons vary in timing, duration and severity.

Seasonal influenza can cause mild to severe illness, and at times can lead to death.

Each year, in the United States, on average:

· 5% to 20% of the population gets the flu;

· 36,000 people die from flu-related complications.

· More than 200,000 people are hospitalized from flu-related causes.

· Ninety percent of seasonal flu-related deaths occur among people 65 years and older.

· About 60 percent of hospitalizations occur in people 65 years and older.

· Illness rates are highest in school-aged children

· Serious complications from seasonal influenza are rare in school-aged children, but they do happen.

· 20,000 children younger than 5 years old are hospitalized each year from flu-related causes. (In children, the risk of hospitalization and death is highest in children younger than 2 years old.)

· On average, about 100 children per year die from flu-related causes. (During the 2007-08 flu season, CDC received reports that 86 children died from influenza-related complications. During the current flu season, CDC has received 59 reports of deaths in children younger than 18.)

· People age 65 years and older, people of any age with chronic medical conditions (such as asthma, diabetes, heart disease, and other conditions), pregnant women, and young children are more likely to get complications from seasonal influenza. The flu can make chronic health problems worse.