Respiratory Protection of Health Care Workers: Antivirals,, Vaccines, and Barrier Devices

Transcription

1 Respiratory Protection of Health Care Workers: Antivirals,, Vaccines, and Barrier Devices Carl H. Schultz, MD Professor of Emergency Medicine Director, Disaster Medical Services UC Irvine School of Medicine

2 Background What s s so different about ph1n1 Atypical seasonal occurrence Poor outcomes associated with younger individuals and pregnant women Little previous herd immunity Health care workers more vulnerable to infection Good news Incidence decreasing, now at usual levels Overall mortality less than seasonal influenza

3 The Problem Need respiratory protection for providers Significant amount of information can be intimidating (lions and tigers and bears) Even reliable entities such as the IOM not infallible (think the Wizard from Oz) What s s the bottom line?

4 The Solution Incapacitate the virus in the body Antivirals or antitoxins Bolster host defenses Vaccination Prevent infection Barrier devices (masks or respirators)

5 Antivirals What drugs ph1n1? Yes: oseltamavir (tamiflu), zanamavir (relenza), IV peramivir (EUA) No: amantadine, remantadine What drugs seasonal influenza ( brand X H1N1, H3N2)?? : amantadine, rimantadine (probably not) No: oseltamavir (tamiflu), zanamavir (relenza)

6 Antivirals Who gets them? Hospitalized patients Children younger than 2 years old (? up to age 5) Adults 65 years and older Pregnant women and women up to 2 weeks from end of pregnancy (95% of cases in 2 nd & 3 rd trimester) People with certain chronic medical conditions (such as asthma, heart failure, chronic lung disease) and people with a weak immune system (such as diabetes, HIV) People younger than 19 years of age who are receiving long-term aspirin therapy

7 Antivirals Who gets prophylaxis (relative indications)? Care givers of children and at-risk adults People who work in large institutions (think nursing homes, prisons, etc) Healthcare workers Persons listed on previous slide

8 Antivirals Does it work? Yes. Early use (within 48 hours of symptoms) reduces: Severity and duration of symptoms Extent and quantity of viral shedding Hospitalizations Complications (pneumonia) Mortality in some populations (pregnancy) For prophylaxis, can prevent illness

9 Antivirals What if I ve I already been vaccinated? Answer: it depends Vaccine not 100% effective 4-10% will not produce immune response Those that do are not immune for 2 weeks after being vaccinated Prophylaxis indicated if vaccinated < 2 weeks from exposure

10 Antivirals How long? 5 days for treatment (sometimes longer) Best outcomes if given in 1 st 48 hours (pregnant women with 4X death/icu admission rate if treated > 48 hours) 10 days prophylaxis Who doesn t t get them? Essentially everyone else Why not? Resistance!

11 Vaccines My baby stopped growing on the exact day I had my H1N1 vaccine. No one even knows the ingredients of what there putting in it for all you know it could be dangerous. I I cannot believe that medical professionals would think that injecting a drug that may contain mercury, formaldehyde, polysorbate 80, phenoxyethanol (antifreeze) and many other toxic ingredients would be SAFE. Dr. Mayer Eisenstein is convinced that vaccines cause autism.

12 Vaccines What is the safety profile for ph1n1 vaccine? Fever Tenderness and swelling at injection site Malaise Guillain-Barre Syndrome

13 Vaccines If you have been willing to receive seasonal influenza vaccine, then you should feel good about the ph1n1. Chickens same as seasonal Eggs same as seasonal Injection and harvesting process same as seasonal Companies/facilities/preservatives you guessed it same as seasonal The only thing different is the virus used.

14 Vaccines Safe (Lancet 1/2010) For every 1million vaccinated, 1 additional case of Guillain-Barre Barre.. In US, 36,000 deaths/year from influenza If vaccinate everyone, save 120 lives for each case of Guillain-Barre Barre. Russian Roulette with a gun that has 1,000,000 chambers, or one that has 6? Do you feel lucky? Well, do ya?

15 Barrier Devices Traditional teaching is that influenza A virus spreads as droplets Large fomites Requires simple physical barrier that air can penetrate. Particles not suspended in air Surgical mask sufficient

16 Barrier Devices Concern by regulatory and scientific bodies: virus can potentially spread as an aerosol Small particles (microns in size) Requires more precise filtering mechanism that still permits air movement Need is for a respirator, at least N-95N

17 Barrier Devices Concerns are reasonable but worries are not proof Can find brown recluse spiders species in Southern California. It can be shown they can inject venom in a lab. But no human cases. Why? Can t t penetrate human skin N-95 cost 10 X that of masks So, what is the evidence?

18 Barrier Devices Evidence for N-95N Can aerosolize virus in certain cases In the laboratory, if you aerosolize influenza virus, it can infect animals. Study in China by Australian investigators reported in an abstract at the September 2009 ICAAC meeting that N-95 N respirators significantly reduced the incidence of ph1n1 infection in hospital workers. Same data presented in August 2009 to IOM

19 Barrier Devices Evidence for surgical masks Large wealth of experience for past 30 years using surgical masks without widespread infection of healthcare providers. No clinical evidence that influenza does, in fact, spread by aerosol in typical patient care settings. At October 31 IDSA meeting, complete China study presented and ahh ahh oops no difference between N-95 N and surgical masks. November 4 JAMA article comparing N-95 N to surgical masks showed no difference.

20 Barrier Devices So what happened to the China study? Study data inaccurately presented 3 groups randomized for investigation 2 using N-95s, N one using surgical masks A fourth group not randomized used cloth masks. This was the control group??!! During review of paper, researchers told not to include this group as controls. Comparing randomized groups showed no difference. Investigator making original presentation received grant money from 3M Company.

21 Summary Antivirals work but should be restricted to those at risk for complications or spreading the infection to large/vulnerable groups The ph1n1 vaccine is safe and you should get it, unless you like playing Russian Roulette with a small gun N-95 respirators are not necessary for general medical patient encounters

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23 Thank you! Questions? Carl H. Schultz, MD