Stories tagged vaccine

Jul
14
2008

Flu vaccine: This is CDC Clinic Chief Nurse Lee Ann Jean-Louis extracting Influenza Virus Vaccine, Fluzone® from a 5 ml. vial.
Flu vaccine: This is CDC Clinic Chief Nurse Lee Ann Jean-Louis extracting Influenza Virus Vaccine, Fluzone® from a 5 ml. vial.Courtesy CDC/Jim Gathany

Did you know back in February scientist and medical professionals selected the influenza virus strains for the upcoming flu season? Now that it is July the pharmaceutical companies are well into manufacturing, purification and testing the vaccine. Meanwhile, it is winter and flu season in the southern hemisphere and the virus is busy mutating. The big question on everyone’s mind is will it mutate so much that the northern hemisphere vaccine will be ineffective?
I agree with Dr. Steven Salzberg remarks in his recent Nature commentary

"The current system, in which most of the world’s vaccine supply is grown in chicken eggs, is an antiquated, inefficient method requiring six months or more to ramp up production, which in turn means that the vaccine strains must be chosen far in advance of each flu season. More crucially it sometimes prevents the use of the optimal strain, as it did in 2007."

Influenza (the flu) is a serious disease
Each year in the United States, on average:

  • 5% to 20% of the population gets the flu;
  • More than 200,000 people are hospitalized from flu complications, and;
  • About 36,000 people die from flu.

Some vaccine problems in the past
In recent years the match between the vaccine viruses and those identified during the flu season has usually been good. In 16 of the last 20 U.S. influenza seasons, including the 2007-08 season, the viruses in the influenza vaccine have been well matched to the predominant circulating viruses. Since 1988, there has only been one season (1997-98) when there was very low cross-reaction between the viruses in the vaccine and the predominate circulating virus and three seasons (1992-93, 2003-04, and 2007-08) when there was low cross-reaction (CDC). So after last year’s miscalculation the committee picked three new strains for the vaccine this year. One is a current southern hemisphere vaccine virus which they expect will still be present next year. In addition, they predict a second new Type A strain, known as H1N1/Brisbane/59, to also hit, along with a newer Type B/Florida strain.

Dr. Salzberg feels last year’s miscalculation was a failure…

"The harm was thus twofold; people fell ill and their trust in the vaccine system was undermined. This failure could have been predicted, if not prevented, through a more open system of vaccine design, a stronger culture of sharing in the influenza research community and a serious commitment to new technologies for production. The habits of the vaccine community must change for the sake of public health."

He goes on to suggest…

"The process of choosing flu-vaccine strains needs to be much more open. Other scientists, such as those in evolutionary biology with expertise in sequence analysis, could meaningfully contribute to the selection. At present, external scientists cannot review the data that went into the decision, nor can they suggest other types of data that might improve it."

Even with all of these miscalculations, I still feel getting the vaccine is worth the risk. But that doesn’t mean the process shouldn’t be improved. So once again I will be vaccinated and I will make sure my family is too—but what can we do as citizens to improve this process? What will you do?

British researchers are developing a vaccine to provide permanent relief to hay fever sufferers.

Dr. John Sampson of Duke University has developed a vaccine which, in early tests, has proven to be remarkably effective against certain types of brain tumors.

The World Health Organization today declared Somalia "polio free." (The last case of polio in the country was reported March 25, 2007; there hasn't been a single infection in the last year.) Health workers wiped out the disease by repeatedly vaccinating all 1.8 million Somali children under age 5.

Polio is extremely contagious and hard to eradicate, and Somalia's achievement is even more amazing given the country's challenges: war, poverty, hunger, no central government, and a lack of detailed medical data.

One more thing: the BBC article linked to above contains this quote from Ali Mao Moallim, a volunteer health worker who also happens to be the last person on Earth to have contracted smallpox:

"Somalia was the last country with smallpox. I wanted to help ensure that we would not be the last place with polio, too."

Awesome.

Mar
05
2008

Red blood cells infected with Plasmodium falciparum: This thin film Giemsa stained micrograph reveals ring-forms, and gametocytes of Plasmodium falciparum.
Red blood cells infected with Plasmodium falciparum: This thin film Giemsa stained micrograph reveals ring-forms, and gametocytes of Plasmodium falciparum.Courtesy cdc

  • Malaria is both preventable and curable.
  • A child dies of malaria every 30 seconds.
  • More than one million people die of malaria every year, mostly infants, young children and pregnant women and most of them in Africa.

A recent article in the NY Times discussed if it is possible to eliminate malaria. They need more money, better health systems and a vaccine. Some experts feel the big push to eradicate malaria is counterproductive or even dangerous. Dr. Arata Kochi, the W.H.O. malaria chief stated in the article that, “… enough money, current tools like nets, medicines and DDT could drive down malaria cases 90 percent. But eliminating the last 10 percent is a tremendous task and very expensive.” He doesn’t want people to have false hope.

A new vaccine
In spite of the debate, research is progressing to reach the goal of eliminating malaria. The Seattle Biomedical Research Institute (SBRI) is home to one of the largest malaria research programs in the United States. SBRI's Malaria Program is focused on vaccine discovery for malaria during pregnancy, severe malaria in children and liver-stage malaria. SBRI scientists are working on a vaccine that uses genetic engineering to render malaria parasites harmless. According to an article in the Seattle Times SBRI is looking for volunteers to be bitten by malaria-infected mosquitoes to aid in the quest for new vaccines and drugs. Scientists will analyze blood from the human volunteers to learn more about the body's immune response to the disease.

What do we do?
Economists believe that malaria is responsible for a ‘growth penalty’ of up to 1.3% per year in some African countries. When compounded over the years, this penalty leads to substantial differences in GDP between countries with and without malaria and severely restrains the economic growth of the entire region. Malaria costs Africa $12 billion every year in lost productivity alone.

What do you think? Where should we be putting our resources?

  • Developing a vaccine (the Bill and Melinda Gates foundation alone has spent $258 million
  • More money to distribute long-lasting insecticidal nets (each net costs $5-7)
  • Mosquito control with indoor residual spraying like DDT (costs nearly $4 per person)
  • Getting effective drug treatments to the infected (effective therapy costs $2.40 for a round of treatment)
Feb
19
2008

Do you have a fever and headache? Is your nose running, with a sore throat and dry cough? Are you tired with muscle aches? You might have influenza or “the flu” as we commonly call it. You may have gotten vaccinated and you still got a bad case of the flu. This is one of those influenza seasons where the experts didn’t quite get it right.

So what happened?
Influenza virus is constantly changing and evolving and each year public health experts get together several months in advance (the FDA will make their recommendation for next year’s vaccine on February 21, 2008) of the flu season to choose three strains of influenza to put in the vaccine, H1N1 strain, H3N2 strain and a B virus strain. It is part science and part art. For more information on this process try your hand at predicting the flu using a program developed as part of the Disease Detective exhibition currently at the Science Museum of Minnesota.

According to Dr. Joe Bresee, the Branch Chief, in the branch of Epidemiology and Prevention of the CDC’s Influenza Division, the H1N1 strain in the vaccine this year is a good match to the circulating strain but the H3N2 type strain and the B strain are not ideal matches. So protection is probably lower than expected in a season when vaccine strains and circulating strains are well matched. Usually, the guesswork is pretty good: Bresee has said, the vaccines have been a good match in 16 of the last 19 flu seasons.

Why are people so sick this year?
It just so happens – and we don’t know why – that H3N2 strains of influenza virus are more severe. For this season the number of people infected with H3N2 influenza is on the rise. The past two years the H1N1 strain predominated and so those infected were not as sick.

What are all these H’s and N’s?
Influenza is categorized as influenza A type viruses and influenza B type viruses. The A viruses are further broken down and characterized by the proteins found on the surface of the virus. These proteins are called hemagglutinin (H) and neuraminidase (N). The proteins change as the influenza virus evolves so numbers are used to designate the different types of H and N proteins.

Remember vaccination is still your best defense against influenza. The experts have been right 16 of the past 19 seasons and as Dr. Bresee reports…

But even in those years where the vaccine matches less well against the circulating strains, we know that getting vaccinated will tend to make the illnesses milder, lessen the chances a person has a very severe outcome.

Jan
29
2008

Often you read about people afraid or worried about vaccines but a recent article published in the Journal of the American Medical Association reports that vaccines have decreased hospitalizations and deaths related to the most vaccine-preventable diseases. And occurrences of these diseases are at an all time low. The researchers compared illness and death before and after widespread implementation of national vaccine recommendations for 13 different vaccine-preventable diseases. These include: diphtheria, invasive Haemophilus influenzae type b, hepatitis A, acute hepatitis B, measles, mumps, pertussis, poliomyelitis, rubella, Streptococcus pneumoniae, smallpox, tetanus and varicella. The data showed large reductions in the number of cases after vaccinations were recommended for each of the diseases. For an interesting view of a vaccine life cycle go to this web site

Vaccines changed medicine
(From the Vaccine Education Center)
Official Rubella Fighter: The “rubella umbrella” campaign urged parents to have their children immunized from this viral infection. Rubella, or more commonly referred to as the German measles, is a mild childhood illness that can pose a serious threat to a fetus, if the mother contracts the illness during pregnancy. More than 20,000 babies were born with congenital rubella syndrome (CRS) during an outbreak of rubella in 1964-65. This epidemic cost the country an estimated $1.5 billion. The rubella vaccine was first licensed in the U.S. in 1969.
Official Rubella Fighter: The “rubella umbrella” campaign urged parents to have their children immunized from this viral infection. Rubella, or more commonly referred to as the German measles, is a mild childhood illness that can pose a serious threat to a fetus, if the mother contracts the illness during pregnancy. More than 20,000 babies were born with congenital rubella syndrome (CRS) during an outbreak of rubella in 1964-65. This epidemic cost the country an estimated $1.5 billion. The rubella vaccine was first licensed in the U.S. in 1969.Courtesy CDC

Vaccines have literally transformed the landscape of medicine over the course of the 20th century.

Before vaccines, parents in the United States could expect that every year:
• Polio would paralyze 10,000 children.
• Rubella (German measles) would cause birth defects and mental retardation in as many as 20,000 newborns.
• Measles would infect about 4 million children, killing 3,000.
• Diphtheria would be one of the most common causes of death in school-aged children.
• A bacterium called Haemophilus influenzae type b (Hib) would cause meningitis in 15,000 children, leaving many with permanent brain damage.
• Pertussis (whooping cough) would kill thousands of infants.
Vaccines have reduced and, in some cases, eliminated many diseases that killed or severely disabled people just a few generations before. For most Americans today, vaccines are a routine part of healthcare.

However, the disappearance of many childhood diseases has led some parents to question whether vaccines are still necessary. Further, a growing number of parents are concerned that vaccines may actually be the cause of diseases such as autism, hyperactivity, developmental delay, attention deficit disorder, diabetes, multiple sclerosis, and sudden infant death syndrome (SIDS) among others. These concerns have caused some parents to delay vaccines or withhold them altogether from their children.
For information on vaccine safety go to this page on the CDC website or this page on the Vaccine Education Center website.

How vaccines work
(from the CDC)

Children are born with a full immune system composed of cells, glands, organs, and fluids that are located throughout his or her body to fight invading bacteria and viruses. The immune system recognizes germs that enter the body as "foreign" invaders, or antigens, and produces protein substances called antibodies to fight them. A normal, healthy immune system has the ability to produce millions of these antibodies to defend against thousands of attacks every day, doing it so naturally that people are not even aware they are being attacked and defended so often (Whitney, 1990). Many antibodies disappear once they have destroyed the invading antigens, but the cells involved in antibody production remain and become "memory cells." Memory cells remember the original antigen and then defend against it when the antigen attempts to re-infect a person, even after many decades. This protection is called immunity.
Vaccines contain the same antigens or parts of antigens that cause diseases, but the antigens in vaccines are either killed or greatly weakened. When they are injected into fatty tissue or muscle, vaccine antigens are not strong enough to produce the symptoms and signs of the disease but are strong enough for the immune system to produce antibodies against them (Tortora and Anagnostakos, 1981). The memory cells that remain prevent re-infection when they encounter that disease in the future. Thus, through vaccination, children develop immunity without suffering from the actual diseases that vaccines prevent. But remember…what's in the vaccine is just strong enough to promote the body's response to make antibodies, but much weaker than the viruses or bacteria in their natural, or "wild," states. For another description see this webpage

A new vaccine designed to fight AIDS has failed to show positive results during its first human tests. Researchers hope to learn what went wrong, and use that to make better vaccines in the future.

Over 90 per cent of the subjects in the phase 1 trials developed an immune response to HIV. The study was conducted by researchers at Karolinska Institutet (KI), Karolinska University Hospital and the Swedish Institute for Infectious Disease Control (SMI).
Read more about the results from Swedish study of HIV vaccine at the Karolinska Institutet web site.

Jul
02
2007

Cervarix, a second vaccine for cervical cancer prevention.

Cervarix vaccine: competition for Gardasil
Cervarix vaccine: competition for Gardasil

Results of the new vaccine, Cervarix, were recently published in Lancet. Report co-author Dr Rachel Skinner said the results were very encouraging.

"We have found through this study that this vaccine is extremely effective in the prevention of pre-cancerous disease of the cervix due to infection with HPV types 16 and 18."
"However we now have evidence that Cervarix offers women broader protection by providing some protection against infections caused by HPV types 45 and 31. These types together with HPV types 16 and 18 account for 80 per cent of cases of cervical cancer worldwide.

Nearly 500,000 new cervical cancer victims each year.

Cervical cancer is a major global health problem, with nearly 500,000 new cases occurring each year worldwide. It is the second most common cancer - and the third leading cause of cancer deaths - in women worldwide. Each year an estimated 270,000 women die from the disease, and it is the leading cancer killer of women in the developing world.

Links to our ongoing discussions on cervical cancer vaccinations.

Source article: GlaxcoSmithKline