Why Older People Have Some Protection Against H1N1

Q: What’s so special about 1957?

A: It’s believed that H1N1 strains went largely out of circulation after 1957, when a new pandemic strain of influenza appeared and caused the pandemic of 1957-58. (A new H1N1 strain reappeared in the mid-1970s and remains in circulation today, but not the same one.) And the CDC has found that serum samples from some people who were born before 1957 indicate some level of protection from the 2009 H1N1 virus. That’s pretty interesting, and, if it is analogous to the situation in 1918, then it’s conceivable that the higher risk for serious infection or death at this time might be more common among those younger people who have risk factors for serious influenza infection.

from http://is.gd/IGNP [ Northwestern University’s Medill school ]

Pandemic Planning Assumptions

These assumptions are being used throughout the U.S. federal government to define a severe case scenario.

- Susceptibility to the pandemic influenza virus will be universal.
- Efficient and sustained person-to-person transmission signals an imminent pandemic.
- The clinical disease attack rate will likely be 30% or higher in the overall population during the pandemic. Illness rates will be highest among school-aged children (about 40%) and decline with age. Among working adults, an average of 20% will become ill during a community outbreak.
- Some persons will become infected but not develop clinically significant symptoms. Asymptomatic or minimally symptomatic individuals can transmit infection and develop immunity to subsequent infection.
- Of those who become ill with influenza, 50% will seek outpatient medical care.
+ With the availability of effective antiviral drugs for treatment, this proportion may be higher in the next pandemic.
- The number of hospitalizations and deaths will depend on the virulence of the pandemic virus. Estimates differ about 10-fold between more and less severe scenarios. Two scenarios are presented based on extrapolation of past pandemic experience (Table 1). Planning should include the more severe scenario.
+ Risk groups for severe and fatal infection cannot be predicted with certainty but are likely to include infants, the elderly, pregnant women, and persons with chronic medical conditions.
- Rates of absenteeism will depend on the severity of the pandemic.
+ In a severe pandemic, absenteeism attributable to illness, the need to care for ill family members, and fear of infection may reach 40% during the peak weeks of a community outbreak, with lower rates of absenteeism during the weeks before and after the peak.
+ Certain public health measures (closing schools, quarantining household contacts of infected individuals, “snow days”) are likely to increase rates of absenteeism.
- The typical incubation period (interval between infection and onset of symptoms) for influenza is approximately 2 days.
- Persons who become ill may shed virus and can transmit infection for up to one day before the onset of illness. Viral shedding and the risk of transmission will be greatest during the first 2 days of illness. Children usually shed the greatest amount of virus and therefore are likely to post the greatest risk for transmission.
- On average, infected persons will transmit infection to approximately two other people.
- In an affected community, a pandemic outbreak will last about 6 to 8 weeks.
- Multiple waves (periods during which community outbreaks occur across the country) of illness could occur with each wave lasting 2-3 months. Historically, the largest waves have occurred in the fall and winter, but the seasonality of a pandemic cannot be predicted with certainty.
from http://is.gd/Cquz

WHO's tally of A/H1N1 cases rises to 11,034

Updated May 21, 2009 10:00 PM

GENEVA (Xinhua) - The world's total number of confirmed A/H1N1 flu cases has risen to 11,034, including 85 deaths, the World Health Organization (WHO) said in a latest update today.

There was an overall increase of 791 cases in the past 24 hours, and most of the new cases were reported by Mexico, the United States, and Canada.

The total number of cases reported by the United States was 5,710, of which 241 were new. Mexico reported a total of 3,892, with 244 new cases, and Canada reported 719, with 223 new cases.

Meanwhile, Japan's total number of confirmed A/H1N1 cases has risen to 259, with 49 new cases. A number of other countries also reported new cases, including Britain, Spain, Costa Rica and Panama.

A total of 41 countries have been hit by the new flu virus.

So far most of the deaths have occurred in Mexico, where the virus was first identified. Infections in countries outside of Mexico are mostly mild ones.

But the WHO has repeatedly warned that the severity of the disease might increase and the world should remain highly vigilant of a possible pandemic.

(from the Phillippines)

Address to WHO Health Assembly

In her address to the Health Assembly, WHO Director-General Dr Margaret Chan noted that the world was facing multiple crises, including the current financial crisis and global economic downturn. In addition to this, it also faced the prospect of the first influenza pandemic of this century.

She said that the world today was more vulnerable to the adverse effects of an influenza pandemic than it was in 1968, when the last pandemic began. The increase in air travel meant that any city with an international airport was at risk of an imported case. Global economic interdependence amplified the potential for economic disruption.

http://www.who.int/mediacentre/news/releases/2009/world_health_assembly_20090518/en/index.html

Advice to businesses on swine flu (from the BBC)

• Employers should make their own individual judgements about whether to stay open
• Businesses should plan for a possible outbreak as they do for all health and safety issues
• Prepare a business contingency plan
• The U.K. Cabinet Office has published a leaflet: Introductory advice to staff on planning for pandemic influenza
• It has also released a checklist of things businesses should be considering
• The checklist suggests companies should identify which parts of their business are critical and consider having a pool of workers who could complete such tasks if necessary, such as contractors or retirees
• Companies should Consider how they would limit face-to-face contact among employees or between employees and customers
• Companies should think about whether their computer systems and communications equipment need upgrading to allow staff to work from home or engage with customers via video conferencing
• Get the latest information on the Department of Health's swine flu website (http://is.gd/BGBk
  

The Human Nose May be Too Cold for Avian Flu

(from the HealthDay News) -- The inside of the human nose is a bit too chilly for the H5N1 avian flu virus, perhaps explaining why the strain has so far not spread easily between people, British and U.S. scientists reported Friday.

According to researchers from Imperial College London and the University of North Carolina, the avian flu virus thrives in the bird gut, where temperatures hover around 40 degrees Celsius (104 degrees Fahrenheit). In contrast, the inside of the human nose -- typically the first site of influenza infection for humans -- stays at about 32 degrees Celsius (89.6 degrees Fahrenheit).

Experiments suggest that avian flu strains cannot grow and replicate in this cooler environment, the researchers said, nor can they effectively kill nearby cells.

Preventing the Flu: Good Health Habits Can Help Stop Germs

As most of you know, we have been studying pandemic influenza for the past year and have developed a software solution to developing pandemic plans. While doing the research, and particularly in the past few weeks, we have uncovered some good sites. Here's some good advice for all of us and a few sites for you to visit as well.

Preventing the Flu: Good Health Habits Can Help Stop Germs

The single best way to prevent seasonal flu is to get vaccinated each year, but good health habits like covering your cough and washing your hands often can help stop the spread of germs and prevent respiratory illnesses like the flu. There also are flu antiviral drugs that can be used to treat and prevent the flu.

1. Avoid close contact.
Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.

2. Stay home when you are sick.
If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness.

3. Cover your mouth and nose.
Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick.

4. Clean your hands.
Washing your hands often will help protect you from germs.

5. Avoid touching your eyes, nose or mouth.
Germs are often spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth.

6. Practice other good health habits.
Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food.


This is an excellent source of current information:
http://www.cdc.gov/flu/weekly/fluactivity.htm

This is also a good site. It is Google's site for following current worldwide outbreaks:

http://maps.google.com/maps/ms?ie=UTF8&hl=en&t=p&msa=0&msid=106484775090296685271.0004681a37b713f6b5950&ll=32.639375,-110.390625&spn=59.906843,114.257813&z=3

WHO believes that the flu pandemic may be unfolding

The World Health Organization is beginning to believe that the flu pandemic may be unfolding. The flu is considered to be mild but the rapid spread has caused WHO to consider that a pandemic is imminent. At the WHO's annual congress, now on in Geneva, many other topics were shelved so that more time could be spent on how to combat the spread of the H1N1 virus. The outbreak began in Mexico and has now spread throughout North America, Europe, Asia, and South America.

There is some speculation that as many as 100,000 people in the United States have caught the virus. If this is true, then the virus likely is spreading between people and that is the forerunner to a virus which will be very hard to control.









http://is.gd/B5x1

Up to 100,000 Americans infected with the H1N1 virus

In the Atlanta Journal, there is an article that says that the CDC scientists now believe that there are up to 100,000 Americans infected with the H1N1 virus.

"Most cases of swine flu occurring in the United States appear to be mild, health officials said.

In fact, "estimates of the confirmed and probable cases in the United States is probably not the best indicator of transmission at this point," the CDC's Jernigan said. "The outbreak is not localized, but is spreading and appears to be expanding throughout the United States. This is an ongoing public health threat."

It's a little hard to estimate the number of people who may be infected with swine flu, Jernigan said, "but if we had to make an estimate, I would say that the amount of activity we are seeing with our influenza-like illness network is probably upwards of 100,000."

Jernigan said there also seems to be more cases of flu generally in the United States -- both the seasonal and the new H1N1 swine flu -- than is usually seen at this time of the year. "There are 22 U.S. states that are reporting widespread or regional influenza activity, which is something that we would not expect at this time," he said."

Read this complete article at:

http://www.ajc.com/health/content/shared-auto/healthnews/cdc-/627172.html

Three aspects of any influenza virus

Virologists are concerned with three aspects of any influenza virus: (1) novelty, (2) transmissibility, (3) lethality. The current H1N1 is novel, that is, we have no antibodies to this strain. Its transmissibility is high but its lethality (percent who die after infection) is still low, except in Mexico. Why it was so lethal in Mexico, no one knows. Will that lethality return as the virus mutates this summer? Keep in mind that the lethality of the 1918 flu was high, perhaps a billion people infected, a half billion became ill, and, at the most, one tenth of a billion died. Until the 2009 virus exposes its lethality, and it may not do so until next fall or winter, we are all playing an involuntary game of Russian roulette.
See this complete article at http://is.gd/ALHS

Beginning of This Blog

We have been posting pandemic news to Twitter ( https://twitter.com/JeffWilliams_ ) for several weeks and we shall begin to cross-post with this blog as well so that the information is easy to find and also lasts longer for archiving. It will also be easier to post longer articles here.