Feb
01
2005

News About The Flu

By | Infectious Disease, Lung Disease, Prevention

Every couple of years new influenza strains seem to develop in Asia and spread thru the rest of the world. When summer comes, the flu season is forgotten and the cycle repeats itself in fall and winter.

Recently there were local outbreaks of two avian influenza strains that according to the name should only affect birds (the “asian bird flu”). Based on research from these two bird flu experiences there seems to be a new way of looking at the development of human influenzas. It appears that new strains of human influenza are born in the bird population of Asia where the virus mutates into new strains. From there it spreads into human care takers (bird-to-human spread) and their contacts. Eventually the virus adapts to the human host and effective human-to-human transmission is incorporated into the DNA of the virus. Now the time is ready for a flu epidemic. It is not clear yet how long this human-to-human transmission switch takes (how many months or years). Here are more details regarding the recent two local outbreaks of asian bird flus:

1. Recently Dr. Arnold Bosman published a study in Holland. He was the health officer in charge of investigating an outbreak of influenza A, type H7N7, affecting a number of chicken farms in Holland between March and May 2003. This was the time of the SARS epidemic that caught all of the media attention at that time. About 86 poultry workers had been infected with flu like illness that caused a viral conjunctivitis of the eyes. However, one veterinarian who was in close contact with the infected birds died from respiratory distress syndrome. Using very sensitive PCR facilitated DNA test they were able to show that these infected people had all the same bird flu with the influenza strain A (type H7N7). When contacts of these people were tested a surprisingly large number, about 1000 with an estimated total of about 2000, people were also positive for antibodies to this particular more harmless strain of bird influenza.

2. The second development is regarding the recent infection of a bird flu in Vietnam that has caused many deaths. This is a much more aggressive influenza A (H5N1), which is the other bird flu that is of concern for the rest of the world. In Vietnam this bird flu type has a mortality of 76%, in other words with this new type of flu 3 out of 4 people die who get it. It all started in December of 2003 and here are the latest details about this flu type.

News About The Flu

News About The Flu

With the new study from Holland the concern among infection specialists is that there likely are a lot more healthy appearing people who become carriers of the disease (like the 2000 contacts in Holland). Experts feel that this type of flu presently might be in the stage of adapting to the human-to-human transmission mode (so far mostly bird-to-human transmission has taken place, which is still a barrier to mass transmission). When the virus has learnt to adapt to human-to-human transmission, there could be a flu pandemic with a new human strain of influenza A (type H5N1) that would rapidly sweep the world.

A Quebec/Canada company (ID Biomedical) is working on an influenza vaccine for the H5N1 virus, in preparation for a possible pandemic. The demand will be so great when a pandemic would happen, that the company is thinking of stockpiling this vaccine so that it would be available when bad news should strike.

In the meantime antiviral antibiotics such as Tamiflu (=oseltamivir) at a dose of 75 mg twice per day for 5 days started within the first two days of the flu aborts the flu effectively according to the experts. Unfortunately this antiviral antibiotic directed against the N1 component of the virus is expensive.

More background information about the flu (medically termed “influenza”): http://nethealthbook.com/infectious-disease/respiratory-infections/flu/

Reference: The Medical Post, Jan. 18, 2005, P. 2 and 56

Last edited October 27, 2014

Jan
01
2004

Flu Season Not Over Yet

By | Health, Infectious Disease, Lung Disease, Prevention

Influenza type A is the cause of many flu epidemics including the one that recently affected the northern hemisphere. It is known to change its surface characteristics from time to time. This has occurred in the southern hemisphere (Australia and New Zealand) during the summer of 2003 and the same new type has caused the recent epidemic in Canada, the US and Europe.

Prior strains of flu viruses in recent years were variants of the Panama strain, that’s why the infection specialists decided in the beginning of 2003 to suggest a Panama strain type vaccine to be used for protection for this flu winter season. However, 70% of the cases tested in Canada by the end of November turned out to be influenza type A/Fujian,full name A/Fujian/411/2002(H3N2), different from type A/Panama, full name A/Panama/2007/99(H3N2), according to Dr. Theresa Tam. She is a specialist in the division of respiratory diseases at the Health Canada Centre for Infectious Disease Prevention and Control. Similar observations regarding a shift from the type a/Panama to the type A/Fujian strain of the flu virus has also been reported in the US and in Europe. It appears that those who have been vaccinated with the type A/Panama vaccine have had partial protection from this new flu as some of the flu virus characterisitics (e.g. the H3N2 determinants) are the same.

Dr. Tam mentioned that the recent deaths in children from the flu in the US, England and Canada would likely be explained by the fact that in the last 3 years there have not been any H3 type flus and the flus that did circulate were relatively mild. This means that children have not developed enough background resistance to fight a flu when it comes. Most adults have background resistance, but older people are loosing some of the resistance due to aging. Dr. Tam explained that not too many children have had the flu vaccination. One would expect that children are most vulnerable for the flu and this explains why these deaths would have occurred.

Flu Season Not Over Yet

Flu Season Not Over Yet

Production of flu vaccines that protect from flus: One of the problems with getting the best match for an upcoming flu season is the lag period between the decision to produce a certain type of flu vaccine and the mass production of the vaccine to serve a world population. This can take 6 to 8 months. A new technique of vaccine production is being investigated, called “reverse genetics”, where the lag period may only be a few weeks.

Dr. Webster, an infectious disease specialist at the St. Jude Children’s Research Hospital in Memphis, has produced a vaccine with this method against an avian flu with the characteristics H5N1(different from the others mentioned above). This is an older flu transmitted by birds that has resurfaced earlier in 2003 again. However, this vaccine that has been produced in cell culture and not in egg cultures, has only been tested in animal models, not in humans yet. Both Dr. Webster and Dr. Tam agree that human trials under FDA guidelines are needed to test these newer vaccines utilizing reverse genetics. Regulatory and patent issues need to be settled for this to happen.

Use of antiviral drugs: Another issue is that type A influenza can be treated with antiviral antibiotics, but every flu season these types of drugs tend to run short. Each country should have a national stockpile of these antiviral drugs (such as Tamiflu) so that enough stock is available in case of a serious epidemic where the vaccine may not fit the flu strain that comes around. This is not happening at the present.

What is needed is that international discussions take place through the Global Health Security Network (right now consisting of the G7 countries and Mexico), Dr.Tam said.

Conclusion: The flu season has started early this season. Many people have died because of a lack of vaccination. Some of those who were vaccinated against the flu may have caught the flu as the fit this year with regard to the vaccine was not the best. However, they likely survived the flu, whereas those who did not have the vaccine were more likely to have experienced the flu more severely and some of these have died. It is not too late to get the flu vaccine before the spring season. Typically there is another peak of the flu between February and April.

Based in part on The Medical Post, Dec.9, 2003 (p.1 and 73).

Last edited December 8, 2012

Oct
02
2003

Flu Shot Cuts Death Rate Into Half

By | Infectious Disease, Lung Disease, Prevention

An earlier publication in the New England Journal of Medicine in March 2003 has shown that the death rate of people 65 years or older who were vaccinated against the flu, dropped into half when they were exposed to the flu and were compared to non-vaccinated controls. On Oct. 9, 2003 Dr. Megan Wren, associate director of the internal medicine residency at Barnes-Jewish Hospital and Washington University School of Medicine, reminded physicians that with the upcoming flu season it is important to include everybody who is healthy at age 50 or older (as the CDC has suggested now for 3 years) with influenza vaccination . Many physicians are still not aware that the rules have been changed to incude younger persons.

Below are recommendations of who should get a vaccination (in table form).

Dr. Wren pointed out that the risk from a flu vaccination is minimal. Contrary to public belief the flu vaccine does not cause fever, unwellness or muscle aches. The only effect is a mildly sore arm at the site of injection.

Flu Shot Cuts Death Rate Into Half

Flu Shot Cuts Death Rate Into Half

This year the FDA has approved a live flu vaccine that is administered as a nasal spray. This is a live modified flu virus that has been “trained” to only multiply in the colder nasal cavity, but not in the warmer airways. Like with all live viral vaccines pregnant women are not allowed to take this.

Who should get the flu vaccine ?
Group of people:
Comments:
all people age 50 or over the immune system weakens with age, that’s why complications of the flu are more common in this age group
women who will be in the 2nd or 3rd trimester of a pregnancy during November through to March protects the fetus from the flu virus in the most vulnerable period of the  development of the fetus
chronic heart disease or lung disease (including asthma) the flu affects the lungs and the heart most readily
chronic kidney or liver disease these chronic diseases weaken the immune system
people without a spleen and cancer patients the immune system is weak in these patients
children and adults with any chronic disease including diabetes chronic illnesses weaken the immune system in young and old
people on imunosuppressive medications the immune system is weak in these patients
all close family members of any of the above people the CDC hopes that this stops the spread of the flu into this vulnerable group of patients

Dr. Wren also mentioned that people with chronic illnesses, with immune deficiencies (e.g. AIDS and cancer patients) and healthy patients over the age of 50 cannot take this live vaccine. All others from age 5 to 49 can take it, but presently this is still very costly (one nasal mist application in 2003 is about 50.00$ US).

Last edited December 9, 2012