Sunday, October 12, 2008

Our First Line Of Defense

 

 

# 2381

 

 

When the next influenza pandemic comes (and scientists tell us it is a matter of `when', not `if'), there are going to be serious limits as to what the government and health officials will be able to do, particularly in the early going.  

 

Vaccines are our best protection, but they take time to create and manufacture.  And beyond that, the logistics of deploying a vaccine to billions of people are enormous.

 

 

For the average American, for the foreseeable future, there will probably be at least a six month wait once a pandemic begins before they can receive a vaccination. 

 

 

Take notice of the emphasis on the words `at least'.

 

And right now, it appears that it will take two shots - a month apart - to confer a reasonable level of immunity.   So you have to add about 6 weeks delay, after you get your first shot, before the vaccine would be effective.

 

Meanwhile, life must go on.  

 

History tells us that a pandemic could easily last 18 months or more. For the first 6, or 8, or even 12 months of a pandemic, most of us will have to find ways to live and work without the protection of a vaccine.  

 

And a vaccine, once it comes, may be only about 70% effective.

 

  

Of course, not all pandemics are created equal.  Some, like the 1968 and 1957 pandemics, were relatively mild.  Sometimes, though we get a truly horrific virus, such as we saw in 1918.   

 

 

But it is important to remember that even in 1918, 70% of the population (who were all probably exposed) never got sick.    Of those that did get sick, in the United States, somewhere around 2%-3% died. 

 

During the worst pandemic in modern history, worldwide, roughly 98 people out of 100 survived.

 

 

While past pandemics aren't reliable predictors of the next pandemic, this should help put things in perspective.

 

 

The CDC has produced a scale that ranks pandemics from CAT1 to CAT5.

 

Pandemic Severity Index

Figure A. Pandemic Severity Index

 

 

 

Thoughts of simply hiding away in your home during a severe pandemic, and waiting until it passes really aren't practical.  Few of us could stockpile enough food, water, and supplies to do so . . . and even fewer  have the financial ability to hunker down for a year or two without working.

 

 

Like it or not, we will all have to learn ways to live with the virus. 

 

 

How do you live, on a day-to-day basis, with a potentially deadly virus in the environment?

 

 

Luckily, there are ways to reduce the risks of exposure during a pandemic, and we have a guidebook.  

 

If you haven't already, download it and read it. It's called:

 

Community Strategy for Pandemic Influenza Mitigation 

(PDF - 10.3 MB)

 

 

While the steps outlined in this document may seem simple, they can, when used together, greatly reduce your chances of infection.  

 

These steps require the use of NPI's, or Non-Pharmaceutical Interventions.   These may include:

 

  • Social Distancing
  • Frequent Hand Washing or Sanitizing
  • Covering your coughs and sneezes
  • School and day care closures
  • Masks, gloves, and other barriers
  • Isolation of those infected
  • Voluntary quarantine of those exposed

 

 

The idea behind NPI's is to slow down the transmission of the virus.   Prevention is the keyword, and the best thing about NPI's is that most don't require special equipment or supplies. 

 

Individually, none of these items is likely to make much of a difference, but when `layered' on top of one another, they can reduce the number of people infected at the same time.

 

 

 

Social distancing is the avoidance of crowds, and trying to keep some separation between you and others.   While the debate over exactly how influenza can be transmitted isn't resolved, most scientists believe that the majority of infections occur at close range via large droplets or from fomites (contaminated inanimate objects).   

 

This `danger zone' is somewhat nebulous, but 6 feet of separation is generally recommended.   Airborne transmission over longer distances is considered by some to be possible, but has never been conclusively demonstrated.

 

While some people have interpreted social distancing as social isolation, and plan to sequester themselves in their homes for weeks or months at a time, that isn't the intent of this NPI.  

 

For social distancing to work, some public events may need to be canceled, employers may need to stagger works hifts, and the use of some forms of public transportation may be curtailed. 

 

 

 

Frequent Hand Washing is often cited as a prime preventative measure, and as an old medic who was used to putting his hands in some pretty awful places, I can attest to the wisdom of doing so.   

 

Old habits die hard, and I still wash my hands 10 times a day. 

 

Influenza viruses can live for hours on inanimate surfaces, depending on the ambient conditions (sunlight, humidity, temperature).  We can pick them up by touching doorknobs, grocery cart handles, telephones, etc.

 

Deadly though they may be, influenza viruses are relatively easy to kill.  Ordinary soap, hot water, and vigorous handwashing can do a pretty good job on the virus.  But to be effective, it must be done properly and often.  

 

Alcohol gel sanitizers are also good, particularly when a sink and soap aren't available.  I carry a small bottle of gel in my pocket, and keep one in my car, for just that purpose.  To be effective, they need to be at least 62% alcohol.  Check the label.

 

 

Covering coughs and sneezes can reduce the transmission of influenza viruses.   In the UK recently they  introduced the  Catch It, Bin It, Kill It   campaign. 

  • CATCH IT - Germs spread easily. Always carry tissues and use them to catch your cough or sneeze.

  • BIN IT - Germs can live for several hours on tissues. Dispose of your tissue as soon as possible.

  • KILL IT - Hands can transfer germs to every surface you touch. Clean your hands as soon as you can.

 

 

graphic

An uncovered cough

(NEJM)

 

Coughing or sneezing into your sleeve is preferable to using your hands. The CDC recommends:

  • Cover your mouth and nose with a tissue when you cough or sneeze.
  • If you don't have a tissue, cough or sneeze into your upper sleeve, not your hands.
  • Put your used tissue in the waste basket.
  • Wash with soap and water.
    or
  • Clean with alcohol-based hand cleaner.

 

 

School Closings are going to be controversial, but in the minds of many people, they will be integral in the slowing down of a pandemic.   As any parent can attest, once a flu bug hits a school or day care center, it doesn't take long for nearly everyone to catch it, and bring it home to their families.

 

It simply isn't possible to maintain safe social distance in a school environment.  Classroom may have 30 or more people in them, desks are lined up next to one another, and hallways are often a seething throng of students making their way to their next class.  

 

It is hard to envision a better place for a virus to thrive than in a school.

 

There are plans to close schools for as long as 3 months at a time, once a pandemic virus begins to spread in this country.   Not everyone is onboard with this policy, and it will certainly cause hardships.  Working parents often depend on schools to watch their kids while they work, and many kids depend on the school lunch program.

 

The alternative, however, is far worse.  Pandemic influenza viruses often have shown a proclivity for the young, and the H5N1 virus is no exception. So far, half of all deaths recorded from the bird flu virus have been in people under the age of 20.

 

 

 

The use of masks and gloves by the general public is controversial because they will be in short supply, must be donned and removed properly, and may inspire unwarranted confidence in the level of protection they will provide. 

 

Over the summer the HHS released proposed guidelines for the use of masks by the public.  In an  Interim guidance on the use and purchase of facemasks and respirators by individuals and families for pandemic influenza preparedness  the American public was given a much stronger recommendation for the home stockpiling, and use, of facemask's and (N95) respirators than we've seen before. 

 

With proper precautions, a single caregiver can use the same respirator several times over a day for brief care visits with the same ill person in the household,[2] so a stockpile of 20 respirators per household would be reasonable.

 

Pandemic outbreaks in communities may last 6 to 12 weeks.[3]  Persons who cannot avoid commuting on public transit may choose to purchase 100 facemasks for use when going to and from work. 

 

 

 

 

Isolation and Quarantine sound draconian, and could be I suppose, but as currently described by the CDC they are simply reasonable precautions.

 

Isolation of the infected will simply mean, if you are sick . . . stay home!   Don't go to work, or to the mall.  Don't spread the virus.

 

Households should be prepared to isolate anyone sickened, as much as possible, from those not yet afflicted.  

 

 

Voluntary quarantine of those exposed is a little more controversial.  It is believed possible to shed the influenza virus for a day or two before showing symptoms. 

 

In other words, you can look perfectly healthy and yet be infectious to others. 

 

A voluntary quarantine asks that members of a household who have been exposed to an infected family member stay home until the incubation period has passed.   

 

This is the reason the government is promoting the idea that every household have sufficient food, water, and medicines for at least 2-weeks.  Many agencies are suggesting up to 3 months worth of food and supplies would be prudent.

 

Note: The implementation of mandatory, or large scale quarantines during a pandemic is viewed by most public health officials as both futile and counter-productive. 

 

For more information on how to prepare, go to GET PANDEMIC READY.

 

 

 

 

 

 

Through the use of these NPI's it is hoped that the rate of transmission, and the number of people simultaneously sickened, can be dramatically cut during a pandemic.  

 

 

The chart above, taken from the PNAS journal article entitled Public Health Interventions and Pandemic Intensity During the 1918 Influenza Pandemic , shows the excess mortality in two American cities.

 

The tall spike represents Philadelphia, while the lower curve represents St. Louis.

 

Scientists believe the startling difference in attack rates, and mortality, in these two cities can be explained by the way each city dealt with the outbreak.

 

In St. Louis, the Health Department closed public venues such as schools, theatres and churches very early in the outbreak, while Philadelphia did not.

 

 

Pretty convincing evidence that these steps can help reduce morbidity and mortality.   And when layered on top of one another, they can make a real difference.

 

For NPI's to work during a pandemic, you need to be prepared to implement them.  That means educating yourself and your family, and laying in any supplies you might need (alcohol gel, facemasks, N95s)  before a crisis.   Frankly, many of these ideas are worthy of using even in a non-pandemic period. 

 

Not only is it good practice for us before facing a crisis, it would likely save lives as well.

 

 

Seasonal flu is responsible for tens of thousands of deaths each year in this country, and hundreds of billions of dollars in losses.  

 

Following these simple precautions would probably greatly reduce the number of infections each year.

 

 

Good enough reason to wash our hands, cover our coughs, get our flu shot, and to STAY HOME if we are sick this winter.