May 20, 2014
News Review From Harvard Medical School -- Study: Faster Vaccine Needed in Flu Pandemic
If a particularly deadly flu virus spread worldwide, saving lives would require much faster vaccine development than occurred in the 2009 pandemic, a study finds. The new study used a computer simulation. Researchers looked at how quickly a deadly influenza A outbreak would spread in a metropolitan area similar to New York City. They assumed that 1,000 people would be infected at the start. Without vaccination, they found that about 48,000 people would die. During the 2009 pandemic, a vaccine was ready for use in 9 months. But in the computer model, vaccinating people after 9 months would reduce the death toll by only about 2,300. Deaths would be further reduced if the vaccine were developed much earlier. The 2009 pandemic was caused by a flu strain known as H1N1. That strain spread fast, but was relatively mild compared with past pandemics. The authors said it's unclear whether the world is better prepared now than in 2009. They said much more needs to be done to develop a vaccine quickly if another pandemic occurs. The journal Annals of Internal Medicine published the study May 20.
By Robert H. Shmerling, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
The outbreak of the H1N1 influenza virus in 2009 was a major health event. Some estimates put the global death toll at more than 575,000.
Once the pandemic was first recognized, there was a lot to do. The strain of the virus had to be identified. Once it was clear that the outbreak was caused by H1N1, a new vaccine was required. That's because this strain had not been expected when the seasonal flu vaccine was developed. The public was notified about the outbreak with advice about hand washing, wearing masks, avoiding crowds and other measures to prevent spread.
As I recall, this happened rather quickly and the efforts were largely successful. But, according to a new analysis, it wasn't nearly fast enough.
Researchers examined what might happen if a deadly strain of flu spread quickly through a large metropolitan area such as New York City. The study looked at how many people would die if there was no vaccine. It also predicted what would happen if a vaccine were provided 4, 6 or 9 months after people began to get sick. In the H1N1 outbreak of 2009, a new vaccine became available about 9 months after the outbreak began.
Here's what the study found:
- Without vaccination or other prevention measures, more than 48,000 people in the metropolitan area would die within a year.
- Vaccination within 4 months of the outbreak would save more than 11,000 lives. And it would save $100 million.
- About 5,700 people and $50 million would be saved if vaccination began within 6 months.
- Only 2,300 people would be saved if vaccination began 9 months after the start of the outbreak.
Interestingly, vaccination that started 9 months into the outbreak combined with routine preventive measures protected people as well as vaccination at 4 months. Preventive measures would include wearing face masks, good hand washing and avoiding others when sick.
The study's authors add that their estimates of benefit from vaccination were probably too high. That's because the analysis did not take into account people most prone to serious illness and death from flu, such as infants and the frail elderly.
The results of this study are sobering. The benefits of vaccination are real, but they won't save everyone from a particularly dangerous strain of influenza. The importance of creating an effective vaccine faster than during the 2009 epidemic is clear.
I think the most important conclusion of this study may be that until we have a vaccine, preventive measures matter even more. People who may be sick with the flu should be very careful to wash their hands, avoid close contacts and wear a face mask whenever others are near. These same measures can be helpful for people who are well but in contact with others who may have the flu.
What Changes Can I Make Now?
Antiviral medicines are available for the flu. But prevention is a much more effective approach. Here's what you can do to reduce the chances you'll develop influenza:
- Get vaccinated each year as early as possible during flu season. This is usually in October or November. Vaccination is particularly important for people at high risk of pneumonia or other complications from the flu. This includes the very young, older adults and those with chronic illness or an abnormal immune system.
- Avoid close contact with people who may have the flu.
- Wash your hands often.
- Urge people who are coughing or sneezing to cover their mouth and nose and to wash their hands.
- Wear a mask if you are coming into contact with someone who may have the flu.
- Talk to your doctor about whether you should take an antiviral medicine before an expected flu outbreak. Medicines used to treat flu include zanamivir (Relenza) and oseltamivir (Tamiflu).
If you already have the flu, you may be able to prevent its spread by good hand washing, wearing a mask and covering your mouth and nose when coughing or sneezing. You also might want to consider taking an antiviral medicine. If taken soon after getting sick, these medicines may prevent spread, help you get better a little faster and prevent further problems such as pneumonia.
What Can I Expect Looking to the Future?
This new study shows the challenges of responding quickly to a new strain of influenza. In the future, you can expect the use of new and faster methods to create life-saving vaccines. However, good hygiene -- frequent hand washing and wearing a face mask -- can be life saving as well. You can expect public health officials to encourage these simple preventive measures.