Booster Shots

Oddities, musings and news from the health world

Category: vaccination

Rodent of the Week: closing in on a universal flu vaccine

July 2, 2010 |  1:00 pm

Rodent_of_the_week universal influenza vaccine Flu viruses mutate rapidly, meaning that vaccines against the flu have to be continually updated to target the latest strains. Moreover, antiviral medications to combat flu sometimes become ineffective because of viral mutations. Thus, finding a so-called universal flu vaccine that could be used against a wide range of viruses over a longer period of time has been a long-held dream of medical experts and the subject of a lot of research.

Scientists reported this week that they have taken another step toward a possible universal flu vaccine. They discovered a target on the influenza A virus that has not changed much -- unlike other regions of the virus -- called influenza matrix 2 protein (M2e). The researchers then found rare, naturally occurring antibodies in humans that target the protein. When these antibodies were given to mice infected with influenza, 60% to 80% recovered compared to a 10% survival rate in the untreated mice. The antibodies protected against two influenza strains: seasonal human H1N1 and an avian flu, H5N1.

The study was completed by researchers at the University of Wisconsin-Madison, University of Tokyo, Johns Hopkins University and Theraclone Sciences of Seattle. It was published Monday in the Proceedings of the National Academy of Sciences.

While humans can produce these antibodies against the M2 protein as part of the immune system's natural response, levels appear to be too low to trigger enough protection. However therapeutic levels of antibodies might create the necessary protection.

-- Shari Roan

Photo credit: Advanced Cell Technology Inc.


Delaying childhood vaccinations does not improve children's health, study finds

May 24, 2010 | 12:11 pm

Child baby vaccination Now that the thimerosal-autism link has been thoroughly discredited, some autism advocates argue that neurodevelopmental problems are caused by overloading children's immune systems with too many vaccines too early in life. As a result, a growing number of parents are asking pediatricians to use alternative vaccination schedules that spread out the shots, even though there is no evidence to suggest that the practice may be helpful. In fact, common sense suggests that it is more likely to be harmful because the highest incidence of infection and mortality from pertussis, for example, occurs in the first six months of life. Failure to vaccinate also exposes other children in the community to infectious diseases that they might otherwise avoid.

Researchers cannot ethically conduct a clinical trial of delayed vaccinations because of the potential risks to the children involved. In an effort to circumvent this problem, pediatric infectious disease specialists Dr. Michael J. Smith and Dr. Charles R. Woods, both of the University of Louisville School of Medicine, analyzed data on 1,047 children enrolled in a previous study designed to determine whether thimerosal produced an autism risk. The children were born between 1993 and 1997, vaccinated by their parents on a schedule of the parents' choosing, and then subjected to a series of 42 neuropsychological tests between the ages of 7 and 10.

Just under half of the children (491 or 47%) received their vaccines on a timely basis, within 30 days of schedule. An additional 235 (23%) received all vaccinations, but not on schedule, and the remaining children received some but not all vaccines. On-time vaccination was most likely to occur among households in which the mother was highly educated and in which household income was higher.

The Louisville duo reported Monday in the journal Pediatrics that delayed vaccinations did not improve outcomes. In fact, outcomes in this group might have been worse. The researchers found that children vaccinated on time performed higher on 15 of the 42 tests than those who were not vaccinated on time. The latter group did not perform higher on any test. The researchers did not offer a potential explanation for this finding, but it may be linked to the higher household incomes.

Current vaccination schedules call for even more shots, so the results are not directly translatable, the authors conceded. But even with the added shots on the new schedule, children are actually exposed to lower doses of antigens because of improvements in the vaccines, they said, so the safety should remain the same.

"This study provides the strongest clinical outcomes evidence to date that on-time receipt of vaccines during infancy has no adverse effect on neurodevelopmental outcomes 7 to 10 years later," the authors wrote. "These results offer reassuring information that physicians and public health officials may use to communicate with parents who are concerned that children receive too many vaccines too soon."

The study was funded internally at the university. Woods has received honoraria from pharmaceutical companies for speeches and has received research funding from them for other projects.

-- Thomas H. Maugh II

Photo credit: Anacleto Rapping / Los Angeles Times


Eradication of smallpox may have set the stage for HIV pandemic, study says

May 18, 2010 | 11:51 am

The worldwide eradication of smallpox in the mid-20th century was a remarkable public health achievement, but it may have set the stage for the HIV pandemic of the latter half of the century, researchers reported Tuesday.

Laboratory tests suggest that immunity to smallpox triggered by the vaccinia (smallpox) vaccine can inhibit the replication of the AIDS virus. Such vaccination could have kept HIV transmission partially under control in the early days of the outbreak, but withdrawal of the smallpox vaccine in the 1950s would have freed it to spread unfettered, the researchers said.

The most common form of HIV is thought to have evolved from a simian immunodeficiency virus found in chimpanzees of southern and western Africa sometime around 1931. It spread slowly until the mid- to late-1950s, when it began to spread exponentially. Wars, misuse of medical equipment and contamination of a polio vaccine have been suggested as possible causes of the spread, but such theories have either been disproved or do not sufficiently explain the behavior of the HIV pandemic, said Dr. Raymond S. Weinstein of the biodefense program at George Mason University in Manassas, Va.

Weinstein and his colleagues noted that the progression of an HIV infection can be mitigated by a co-infection with certain other viruses, such as human herpesvirus 6 or 7 or the paramyxovirus that causes measles. Such viruses interfere with a cellular receptor of white cells that is also used by HIV. The vaccinia virus also blocks this receptor.

To test their idea, Weinstein and his colleagues recruited 20 Navy personnel. Half had received normal vaccinations and half had received both those vaccinations and, within the previous three to six months, vaccination against smallpox. The researchers extracted white blood cells from all the subjects and exposed them to HIV in a culture dish. They reported in the journal BMC Immunology that HIV replication was slowed by about 80% in the cells from those who had received smallpox vaccination.

"While these results are very interesting and hopefully may lead to a new weapon against the HIV pandemic, they are very preliminary and it is far too soon to recommend the general use of vaccinia immunization for fighting HIV," Weinstein said in a statement. Given the great difficulties researchers have encountered in trying to develop an HIV vaccine, the ironic fact is that we may once have had a vaccine that is more effective against the virus than anything that has since been developed, and we threw it away.

-- Thomas H. Maugh II


Mumps, whooping cough, measles ... Maybe vaccines are a good idea after all

May 17, 2010 |  1:07 pm

Vaccine Those so-called diseases of childhood -- mumps, measles, whooping cough -- haven't been defeated.

As L.A. Times staff writer Rong-Gong Lin II describes in this article, East Coast mumps outbreak may be spreading to L.A.:

"Nine cases of mumps have been reported so far this year, two more than were seen in all of 2009, according to county health officer Jonathan Fielding.

There is also a rise in whooping cough cases, which killed two infants in L.A. County this year, and an increase in measles cases to four so far in 2010, up from one last year."

If the deaths give you pause, here's contact information for the L.A. County Department of Public Health's immunization program.

And here's vaccine information from the federal Centers for Disease Control and Prevention (named for its purpose, not the catchy sound).

-- Tami Dennis

Photo credit: Los Angeles Times


The FDA says it's safe to use rotavirus vaccines

May 14, 2010 | 11:13 am

The Food and Drug Administration on Friday said that it is safe to resume the use of the Rotarix rotavirus vaccine and to continue the use of the RotaTeq rotavirus vaccine. The agency in March had cautioned physicians to stop using Rotarix because the manufacturer had found trace amounts of a pig virus in the vaccine. Both the FDA and the manufacturer of the RotaTeq vaccine then found traces of the pig virus in it as well.

Following extensive studies by the manufacturers and the FDA, however, the agency said there is no risk from the viruses, called porcine circovirus 1 and 2. The viruses do not infect humans and are not known to cause any diseases, either in humans or pigs themselves. Moreover, "the vaccines have strong safety records, including clinical trials involving tens of thousands of patients, as well as clinical experience with millions of vaccine recipients."

A report from the Centers for Disease Control and Prevention on Wednesday estimated that the vaccines are preventing more than 50,000 hospitalizations of infants in the United States each year. Rotavirus infections, which are thought to kill as many as half a million children worldwide each year, are characterized by diarrhea and severe dehydration. The benefits of the vaccine, the FDA said, far outweigh any risks, which are only theoretical.

-- Thomas H. Maugh II


Rotavirus vaccines reduce hospitalizations in kids, study finds

May 12, 2010 |  4:26 pm

The introduction of the first rotavirus vaccine in the United States in 2006 led to sharp reductions in hospitalizations for gastroenteritis, an inflammation of the stomach and intestines that is marked by diarrhea and dehydration, researchers reported Wednesday. Rotavirus is one of the leading causes of gastroenteritis and was thought to be the cause of an estimated 55,000 to 70,000 hospitalizations in the United States each year before the introduction of the vaccine, Rotateq, in 2006 and the introduction of a second vaccine, Rotarix, two years later.

Epidemiologist Aaron T. Curns of the Centers for Disease Control and Prevention and his colleagues studied hospitalizations for gastroenteritis in 18 states accounting for almost 50% of the U.S. population. They compared rates for children hospitalized from 2000 to 2006 to those in the following two years. The team reported online in the Journal of Infectious Diseases that hospitalization rates for acute gastroenteritis dropped by 16% in 2007 and by 45% in 2008 compared with the earlier period. They estimated that about 55,000 hospitalizations were prevented during 2008 by the vaccinations, suggesting that the vaccine was highly effective at preventing most rotavirus cases.

The vaccines have been in the news recently because researchers have detected trace contamination of them by a pig virus that does not infect humans and that apparently causes no illness. In March, the Food and Drug Administration cautioned doctors against using the Rotarix vaccine because of the contamination. An FDA advisory panel earlier this month, however, said that both vaccines appeared safe and physicians should feel free to use them. The FDA has not yet issued a formal recommendation.

— Thomas H. Maugh II


FDA panel members support continued use of both rotavirus vaccines despite trace contaminants

May 7, 2010 |  3:38 pm

Members of a Food and Drug Administration advisory committee meeting Friday urged physicians to continue using both commercial rotavirus vaccines despite evidence that both carry trace contaminants from a harmless pig virus. The panel did not take a formal vote on a recommendation, but a majority of participants said they thought the benefits of the vaccine far outweigh any potential risk. An agency spokeswoman said it would make no immediate recommendation on the vaccines, but would act expeditiously to come to a decision.

The FDA had recommended in March that physicians stop using one of the vaccines, trade-named Rotarix, because of the contamination, but said then that it had not found the contaminant in the second vaccine, called Rotateq. But the panel was told Friday that newer, more sensitive tests had detected minute amounts of two viruses, called porcine circovirus 1 and 2 (PCV1 and PCV2), in Rotateq. PCV1 was also found in Rotarix. Neither virus is known to infect or cause illness in humans, and no adverse effects have been observed in children who have received either of the vaccines.

Rotavirus causes severe diarrhea and dehydration and is thought to cause more than 500,000 deaths each year in infants globally. Before the introduction of Rotateq in the U.S. in 2006, the virus caused an estimated 50,000 infant hospitalizations each year. Epidemiologist Umesh Parashar of the Centers for Disease Control and Prevention told the panelists that the vaccines have produced almost "a complete wipeout" of rotavirus infections in this country.

It is not known how the pig virus got into the vaccines, but the FDA and the companies that make the vaccines speculate that it was a contaminant of the pig enzyme trypsin, which is used in manufacturing the vaccine.

Experts agreed that the contaminant is only present in minute quantities -- quantities so small, in fact, that it could not be found with tests used when the vaccines were licensed. It has only been the development of new techniques for identifying extremely small traces of DNA that has allowed researchers to find its footprints.

-- Thomas H. Maugh II


Doctors want you to remember polio and diphtheria

April 27, 2010 |  6:00 am

Polio Too many American children do not receive recommended childhood vaccines for illnesses such as polio, measles, mumps, diphtheria and pertussis that were once thought to have been eradicated but are making a comeback in some areas. According to data from 2008, almost one-quarter of children ages 19 months to 35 months did not receive the recommended vaccinations.
 
On Tuesday, the American Academy of Pediatrics -- perhaps frustrated with the stubborn anti-vaccine tide in the United States -- unveiled a new public health campaign called Protect Tomorrow that "brings to life the memories of the terrible diseases of the past and reminds parents that, unless they are vaccinated, infants and children are at risk for contracting infectious diseases that can lead to hospitalization, disability and even death," according to a statement from the organization.
 
Some children don't receive vaccines because they don't have regular access to healthcare. Others have ample access to care but have parents who are afraid of the potential side effects of some vaccines or believe vaccines cause autism. The autism link has been disproved. It's true that vaccines may carry side effects, although side effects are severe in a very small number of children. However, if trends continue and more children go unvaccinated, we may have a return of severe communicable diseases that will harm many more children than would be imperiled by the vaccines. Young parents today are simply not familiar with the horrors of the iron lung or the tragic infant deaths from pertussis that were all too common more than a half-century ago.
 
It may be a fear tactic, but the AAP is right to warn that history may repeat itself. Vaccination is for the good of everyone. It's time parents consider logically the public health value of vaccination -- one of the great advances of 20th century medicine -- weighed against the tiny chance of adverse side effects occurring in their child.
 
Information on the campaign and National Infant Immunization Week, April 24-May 1, is available at www.ProtectTomorrow.org

-- Shari Roan

Photo: A girl receives a polio vaccination in 1954. Credit: Joe Heiberger /  Washington Post


Women need immunizations, but who could give them? Who?

April 20, 2010 |  6:14 pm

Pertussis - Wait a minute! What if women got at least some of their immunizations at the ob-gyn's office?

- You know, it's crazy enough ... it just might work!

Such is the conclusion from Duke University researchers trying to figure out how to improve immunization rates among women. They set up a pilot program at three North Carolina ob-gyn offices to offer vaccinations against human papillomavirus and tetanus, diphtheria and pertussis.

The program boosted rates of HPV vaccination, but its shining success was for the percentage of women who accepted the so-called Tdap shot. In one office, preliminary data shows, vaccination rates among postpartum patients soared, from 16.7% to 85.7%.

Rates of pertussis, more commonly known as whooping cough, have been on the rise in recent years. As the CDC notes in its information about pertussis: "More than half of infants less than 1 year of age who get the disease must be hospitalized." Often, the illness can be traced to siblings or adults who don't even know they're infected.

Here, Medline Plus offers information on diphtheria, tetanus and HPV.

The results shouldn't surprise -- except for the fact that such vaccinations aren't more common. An obstetrician-gynecologist is often the one physician whom female patients see with any regularity.

(Even women not seeking prenatal or postpartum care are diligent about the annual visit. For that, thank the Pap smear. This L.A. Times story, Group Recommends Less-Frequent Pap Tests, calls the test the most successful cancer screen in history. It notes that the test fueled awareness of women's sexual and reproductive health and that it's the reason some women get such preventive medical care.)

Preliminary findings of the women's immunization study were presented Tuesday at the CDC National Immunization Conference.

Here's Duke University Medical Center's news release on the pilot program, A Vaccine Program for Women.

-- Tami Dennis

Photo: Immunization against pertussis, or whooping cough, wanes over time. A booster is recommended. Credit: Los Angeles Times


The FDA warns against using Rotarix rotavirus vaccine--at least temporarily

March 22, 2010 | 11:49 am

The Food and Drug Administration on Monday warned doctors and parents against using the Rotarix rotavirus vaccine until further testing can confirm that it is safe. The warning follows the discovery by an academic research group--subsequently confirmed by the FDA and Rotarix manufacturer GlaxoSmithKline -- that the vaccine contains a pig virus called porcine circovirus 1 or PCV1. The virus is not known to cause illness in humans, and no adverse effects have been observed in children vaccinated with Rotarix, but the agency decided to err on the side of caution with the warning until more information can be obtained.

For the time being, the agency recommends that pediatricians use a competing vaccine, RotaTeq, manufactured by Merck. Preliminary tests have found no traces of PCV1 in this vaccine.

Rotavirus causes severe diarrhea and dehydration and is thought to cause more than 500,000 deaths in infants worldwide each year, primarily in low- and middle-income countries. Before the introduction of RotaTeq in the U.S. in 2006, the disease caused an estimated 50,000 hospitalizations and several dozen deaths each year. Rotarix was introduced in 2008 and most U.S. children who have been vaccinated against rotavirus have received RotaTeq, the FDA said.

The agency is now attempting to determine whether the vaccine contains intact PCV1 or simply viral fragments, as well as how it got into the vaccine. The agency said it will convene an expert advisory panel in four to six weeks to make further recommendations.

The World Health Organization and the European Medicines Agency are expected to release statements Monday confirming current guidelines for using the drug. They will argue that the benefit from the vaccine far outweighs any potential risk, according to a statement by GlaxoSmithKline.

An estimated 69 million doses of the vaccine have been administered globally. Estimated worldwide sales of the vaccine in 2009 were $425 million, the company said.

-- Thomas H. Maugh II



Advertisement


The Latest | news as it happens

Recent Posts
test |  March 15, 2011, 4:00 pm »
Booster Shots has moved |  July 12, 2010, 6:02 pm »


Categories


Archives