Will CDC’s Bird Flu Vaccine Work if Virus Mutates?

Will CDC’s Bird Flu Vaccine Work if Virus Mutates?

The move by U.S. health officials to start making a vaccine against the new strain of bird flu is a good idea, regardless of whether the virus ultimately changes, as flu viruses often do, experts say.

On Thursday (April 4), the Centers for Disease Control and Prevention (CDC) said it had begun work on a vaccine against H7N9, a new bird-flu virus causing illness in China. So far, health officials have reported that 16 people have become sick with the virus, six of whom died. Currently, the virus does not appear to spread between people.

The CDC plans to “build” the virus to use it in its vaccine, rather than wait for a sample to ship from China, the New York Times reported. Using the H7N9 genetic sequence as a blueprint, CDC researchers will synthesize genes for part of the virus and attach them to the “backbone” of another virus known to grow well in labs, the Times said. Making the vaccine is just a precaution — health officials aren’t sure yet if they’ll need to use it.

NEWS: Pandemic? How Mutant Bird Flu Goes Airborne

“I think it’s a good idea to start with anything we can,” said Dr. Arnold Monto, a professor of epidemiology at the University of Michigan School of Public Health. He noted that it could take at least a month to make even a provisional vaccine, and six months to manufacture one that can be used on a wider scale.

Even if the H7N9 virus changes during the time it takes to make a vaccine — for instance, the virus could mutate so that it’s able to spread between people — having a vaccine will still be an advantage.

“Protection, even if it’s partial protection, is better than no protection,” Monto said.

Dr. Richard Webby, a bird-flu expert and infectious disease researcher at St. Jude Children’s Research Hospital in Memphis, Tenn., said that while there’s a possibility the virus could mutate to spread between people, such a change would not necessarily impact the effectiveness of a vaccine that we make now.

Starting early is important because it could take some time to figure out how to make an effective vaccine. Researchers know from previous experience with this family of viruses (H7 viruses) that people may need two shots in order to build up immunity, and the vaccine might need an additional component, called an adjuvant, to boost its effectiveness, Monto said.

NEWS: New Bird Flu Strain in China Prompts Pigeon Kills

If the H7N9 virus is still causing illness by the time researchers are finished making a provisional vaccine, known as a seed vaccine, it’s almost certain that at least some batches will be manufactured (though not necessarily used), Webby said. However, before it’s manufactured, it will need to undergo safety tests, Monto said.

Researchers are concerned about H7N9 not only because it’s novel, but also because it has genetic markers that suggest it has adapted to grow in humans. However, it’s possible this marker only shows up once the virus infects people, and the virus does not naturally have this marker when it infects birds, Webby said. Researchers need to find the source of the virus — be it birds or another organism — to know whether the marker is inherent in the virus.

Today (April 5), the CDC said there is no need for the general public to be alarmed about this virus, because it does not appear to be spreading between people, according to NBC News.

Antiviral medications appear to work against the virus, which is good news, Monto said. However, antivirals have not yet been used to treat patients with H7N9, according to the World Health Organization. (The medications must be given very early on in the course of infection in order to be effective.)

Pass it on: Starting work on a vaccine against the new bird flu is a good idea, experts say.

More from MyHealthNewsDaily.com:

This article originally appeared onMyHealthNewsDaily.com. Copyright 2013 MyHealthNewsDaily, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


China reports 2 more cases of new bird flu virus

China reports 2 more cases of new bird flu virus


BEIJING (AP) — Shanghai has reported two more cases of human infection of a new strain of bird flu, raising the number of cases in eastern China to 18. Six of the people who contracted the virus have died.

Health officials believe people are contracting the H7N9 virus through direct contact with infected fowl and say there’s no evidence the virus is spreading easily between people.

Shanghai’s government said Saturday the latest victims are a 74-year-old peasant and a 66-year-old retiree. The city has been ordered by the agriculture ministry to halt its live poultry trade and slaughter all fowl in markets where the virus has been found.

The capital cities of the neighboring provinces of Zhejiang and Jiangsu also have suspended sales of live poultry. Both provinces have reported H7N9 cases.

New Bird Flu Strain in China Prompts Pigeon Kills

New Bird Flu Strain in China Prompts Pigeon Kills

Six deaths announced in the past six days from a new strain of bird flu in China has led authorities to kill all of the pigeons being sold for meat at a Shanghai market.

The virus, H7N9, has infected at least 14 people so far, most likely through direct contact with birds. No person-to-person transmission has been detected, but health officials and scientists are closely monitoring the virus for similarities to past outbreaks.

NEWS: Formerly Banned Bird Flu Studies Suggest Pandemic

This particular strain may be trickier to detect because it can infect birds without any noticeable effect on their health, The Associated Press reports.

“In the past usually you would see chickens dying before any infections occurred in humans, but this time we’ve seen that many species of poultry actually have no apparent problems, so that makes it difficult because you lose this natural warning sign,” David Hui, an infectious diseases expert at the Chinese University of Hong Kong, told The Associated Press.

Virus-Like Particles May Fast-Track Vaccines

The virus may have undergone a recent mutation that makes it easier to pass on to other animals, scientists have said. Health officials put those who work closely with birds on alert. Some of the 14 people infected were sicked weeks ago, but weren’t diagnosed with H7N9 until recently.

Although pigeons have been identified as the carriers so far, it’s likely that other types of poultry are also carrying the virus, Hui said.

China bird flu mutates, might infect mammals

China bird flu mutates, might infect mammals


BEIJING (AP) — In a worrisome sign, a bird flu in China appears to have mutated so that it can spread to other animals, raising the potential for a bigger threat to people, scientists said Wednesday.

So far the flu has sickened nine people in China and killed three. It’s not clear how they became infected, but there’s no evidence that the virus is spreading easily among people.

But the virus can evidently move through poultry without making them sick, experts said, making it difficult to track the germ in flocks.

The findings are preliminary and need further testing.

In the wake of the illnesses, the Chinese Center for Disease Control and Prevention shared the genetic sequence of the H7N9 virus with other scientists to help study how the virus might behave in different animals and situations.

One scientist said the sequence raises concern about a potential global epidemic, but that it’s impossible to give a precise estimate of how likely that is.

“At this stage it’s still unlikely to become a pandemic,” said Richard Webby, director of a World Health Organization flu center at St. Jude Children’s Research Hospital in Memphis, Tenn.

“We should be concerned (but) there’s no alarm bells ringing yet,” he said.

The virus has genetic markers that would help it infect people, Webby said. That makes him worry about a pandemic a bit more than he does for other bird flu viruses, such as the H5N1 virus that emerged a decade ago, he said.

“The tentative assessment of this virus is that it may cause human infection or epidemic,” said Dr. Masato Tashiro, director of the WHO’s influenza research center in Tokyo and one of the specialists who studied the genetic data, “It is still not yet adapted to humans completely, but important factors have already changed.”

Flu viruses evolve constantly, and scientists say such changes have made H7N9 more capable of infecting pigs.

Pigs are a particular concern because bird and human flu viruses can mingle there, potentially producing a bird virus with heightened ability to spread between humans, said Dr. William Schaffner, a flu expert at the Vanderbilt University School of Medicine. That’s what happened in 2009 with swine flu.

The scientists who inspected the genetic data also said that based on information from the genes and Chinese lab testing, the H7N9 virus appears able to infect some birds without causing any noticeable symptoms. Without obvious outbreaks of dying chickens or birds, authorities could face a challenge in trying to trace the source of the infection and stop the spread…Read more