A/H1N1 to become dominating flu strain in North Hemisphere's this winter

[Pathfinder]

Interview: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

2009-08-18 19:23:43

MANILA, Aug. 18 (Xinhua) -- The A/H1N1 influenza is expected to become the dominating strain in the North Hemisphere's upcoming winter, crowding out normal seasonal flu and causing more deaths, said a regional spokesman of the World Health Organization (WHO) on Tuesday.

"The virus is unstoppable now. It's inevitable that we are going to see more infected cases, and unfortunately more deaths, as the North enters winter," John Larking, communication specialist of the WHO Western Pacific Region, told Xinhua in an interview on Tuesday.

Influenza normally takes off in winter months. Australia, Argentina, Chile and other South Hemisphere countries all experienced a spike of A/H1N1 flu cases and related deaths in the past winter.

Larking said the WHO has been officially notified of 50 A/H1N1 influenza-related deaths in the Western Pacific region which covers East and Southeast Asia and Oceania, but the combined fatality counts by the region's health authorities have mounted to169 by Aug. 12, according to the WHO website.

Though a mild pandemic, the A/H1N1 influenza has shown able to cause serious illness and death among certain groups of people, Larking said, and developing countries with an under-resourced health system but large number of poor people will face extra challenges.

The vaccines can only be available for several countries by September and there is always possibility that the virus might mutate into a more dangerous strain, Larking said.

In the absence of vaccines, one lessen that can be learnt from the South's battle with A/H1N1 is that people who belong to the high risk group should seek treatment early, best within 48 hours after they fall ill. Patients who developed serious complications or died often sought treatment too late, Larking said.

The WHO considers people with cancer, HIV/AIDS, chronic respiratory conditions, cardiac disease, diabetes, might be higher risk to the A/H1N1 influenza, along with pregnant women, the morbidly obese, and smokers.

Seven countries in the region with high maternal mortality rates -- Cambodia, Laos, Papua New Guinea, the Philippines, Vietnam, Mongolia and China -- face greater risks of the pandemic.

Larking said the start of a school year might also be an issue but the WHO does not make "fast and hard" recommendations on school closures. Also left to national governments' discretion are their response strategies.

Though several countries in the region have shifted from containment to a mitigation phrase in response to the pandemic, which means they no longer test all suspected cases and focus more on treatment, Larking said there is no a universal strategy shift recommendation from the WHO.

http://news.xinhuanet.com/english/2009-08/18/content_11905060.htm

 

[Mamabird]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

This might actually be a good thing as long as the Swine Flu virus doesn't change.

It's H3N2 that is deadly. If Swine Flu takes over, the US might then see lots of flu during the season, but deaths lower than in the last two winters.

 

[Andy2000]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

If the H1N1 virus remains stable - why would the US fall picture be different to say Brazil's recent winter one? Brazil has similar population number though the US health system may be better equipped and may have a vaccination program. I suppose one might argue that with more infections the chance of mutation increases but then when the 1918 mutated (if it did) it happened before the beginning of a lethal 2nd wave not in the later stages of it. Why should the Northern Hemisphere experience a different picture than the Southern Hemisphere?

 

[Snowy Owl]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

For insured US citizens and for Canadians Health access makes a differences just as paved roads to get to the nearest hospital in regions.

Multiply this access by thousands and there's the differences.

Snowy

 

[gsgs]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

it's not clear whether H3N2 will die entirely.

It wasn't wiped out in 1977 nor in several H1N1-years
since then. It always returned.

Maybe we should support the process, maybe we should
take care that newflu dominates everywhere at the same time,
i.e. in South East Asia,
and there remains no place for H3N2 to survive

 

[Andy2000]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

Didn't H3N2 escape from the vaccine recently?

 

[Snowy Owl]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

H3N2 will be part of the seasonnal trivalent vaccines
http://www.who.int/csr/disease/influenza/200902_recommendation.pdf

Snowy

 

[Corn]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

Didn't H3N2 escape from the vaccine recently?

Maybe and yes, Their is a strain of H3N2 that is circulating that has "drifted" away from the seasonal VAX. Let's hope it doesn't become predominate this season but it looks to be headed that way.

The thread is around here somewhere.

So if the H3N2 seasonal VAX misses it's target the elderly who have largely been spared H1N1/09 could be wammoed by the drifted H3N2.

As my doctor said, "It is going to be an interesting flu season."

 

[Corn]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

Siegfried X @ FT

H3N2 variant mismatched with seasonal vaccine


Mismatched H3N2

TORONTO ? Another storm may be brewing for the coming flu season: A component of the seasonal flu shot may not be well matched to the circulating viruses, potentially setting up what's known as a vaccine mismatch.

Some samples of the emerging new strain of H3N2 viruses show a substantially reduced response to antibodies generated by the corresponding virus in the seasonal vaccine, raising the possibility of significantly reduced protection in some cases.

Vaccine mismatches are bad at the best of times. More people get sick during flu seasons with mismatches. But a seasonal flu vaccine mismatch coinciding with a flu pandemic? That is no one's idea of a good time.

Dr. Allison McGeer groaned when she heard a new H3N2 variant is circulating in some parts of the Southern Hemisphere.

"It's going to be a long winter. I know that already," said McGeer, an influenza expert and head of infection control at Toronto's Mount Sinai Hospital.

"It's not going to be pleasant because ... it's going to be one big long influenza season, from some time in September until next May."

The new variant has been seen on a number of continents, though it still remains a minority member of the H3N2 family, according to experts at the World Health Organization and the U.S. Centers for Disease Control in Atlanta.

With the demands the ongoing pandemic is placing on the WHO's laboratory network, researchers haven't yet had time to study whether the new variant is making up a growing percentage of H3N2 viruses, said Dr. Nancy Cox, director of the CDC's influenza division.

If they were, that would suggest the variant was on its way to becoming the dominant H3N2 virus and a vaccine mismatch would be on the cards.

Further clouding the issue is the fact that labs around the world haven't been submitting as many H3N2 viruses to the WHO network. There are simply fewer of them around.

"We haven't had that many H3N2 viruses to analyze because we've had such a flood of the novel H1N1 viruses because they're predominating," Cox said.

Dr. Wenqing Zhang of the WHO's global influenza program said many Southern Hemisphere countries are just coming into their regular flu seasons.

The next month or so will give the world a clearer picture as to whether the pandemic virus will crowd out the previous influenza A subtypes - making the composition of the seasonal vaccine less relevant - or whether one or both of the seasonal flu A virus families will continue to circulate.

And if H3N2 sticks around, the coming weeks will also offer a sign as to whether this new variant is likely to complicate the upcoming Northern Hemisphere flu season.

"While seemingly this variant H3 is emerging, we do not know to what extent it will be circulating," Zhang said by email from Geneva.

Cox said the WHO collaborating labs will be heightening surveillance for seasonal flu viruses in the lead-up to the WHO's strain selection meeting for the Southern Hemisphere seasonal vaccine, held in September.

One place they'll be checking is virus samples from nursing homes. H3N2 viruses prey on seniors and are behind many of the frequent flu outbreaks seen in long-term care facilities. For some reason, nursing home outbreaks are rarely caused by seasonal H1N1 viruses and so far the pandemic H1N1 has largely spared that population too.

"If we start to see outbreaks in those types of settings, this would increase our level of concern," Cox said. "We haven't seen that to date."

Because it takes months to make and ship flu vaccine, the viruses covered by the seasonal flu shot have to be chosen long in advance.

For the Northern Hemisphere vaccine, experts like Cox gather at the WHO in February to assess the viruses circulating and make their best estimates of which will be the major disease sources in the following winter.

For the 2009-2010 winter they chose an H3N2 virus called A/Brisbane/10 first spotted in 2007.

But within weeks of the decision hints emerged there was a new H3N2 variant, one sufficiently mutated ("drifted" in the language of flu) that it might be able to evade the vaccine.

Researchers in the influenza lab at the British Columbia Centre for Disease Control spotted it in early March as they were conducting late-season surveillance looking for just such viral evolution. In early May, they reported the finding on ProMed, an electronic bulletin board and mailing list which monitor infectious diseases outbreaks around the world.

Dr. Danuta Skowronski, an influenza expert at the BCCDC, said she is expecting this new variant to take over as the dominant H3N2 strain. And since the swine flu virus isn't infecting older adults much, it could leave a niche for the new H3 variant.

"So it's hard to know. We just have to prepare for that possibility either way," Skowronski said.

"The idea of having a mismatched drift strain circulating the same year that we also have swine influenza may mean that all segments of the population are affected by influenza one way or the other, whether it's the elderly with H3N2 and the young with H1N1."

http://www.google.com/hostednews/canadianpress/article/ALeqM5jPDEE_BdufsSNIxDs5NN-W0GiWoQ

 

[HenryN]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

This might actually be a good thing as long as the Swine Flu virus doesn't change.

It's H3N2 that is deadly. If Swine Flu takes over, the US might then see lots of flu during the season, but deaths lower than in the last two winters.

Hong Kong is 50/50 with swine H1N1 and H3N2.

 

[Pathfinder]

Re: A/H1N1 to become dominating flu strain in North Hemisphere's this winter

From Corn:

Quote:
"Another storm may be brewing for the coming flu season: A component of the seasonal flu shot may not be well matched to the circulating viruses, potentially setting up what's known as a vaccine mismatch."


Is this true?