Maryland DHMH 2009 H1N1 Update for Clinicians

2009 H1N1 Update
Maryland surveillance efforts have determined an increase in influenza activity, starting early September, 2009. Statewide surveillance systems have detected increased visits for influenza-like illness symptoms to both doctor’s offices and emergency rooms. With the onset of school, increased school and college outbreaks have been detected. Influenza activity in Maryland has been reported to CDC as widespread. DHMH has initiated surveillance for antiviral resistance, detecting none to date. CDC reports its first documented case of probable transmission of oseltamivir-resistant H1N1 from summer camp youth on oseltamivir chemoprophylaxis. CDC currently reports a nationwide increase in influenza activity, notably in the Southeast region. No increase in 2009 H1N1 influenza severity has been detected, and WHO reports ongoing activity in Southern Hemispheres. See www.dhmh.state.md.us/swineflu and www.marylandfluwatch.org.

2009 H1N1 Vaccination Efforts
As of September 14, Maryland DHMH reports a total of 2,140 pre-registrants for the 2009 H1N1 vaccine. Provider agreements and mechanisms for tracking administered doses will be sent to pre-registrants this month. Final details on insurance reimbursement for vaccine administration are forthcoming. Mechanisms for tracking adverse effects of virus are under development. Passive surveillance for adverse effects will be performed, in part, through provider reporting to the VAERS system at www.vaers.hhs.gov. Active surveillance for severe side effects will be performed by CDC, in conjunction with Maryland DHMH. Details on all of the above will be updated on www.dhmh.state.md.us/swineflu.

DHHS has released information on recent clinical trials of monovalent 2009 H1N1 vaccine. A robust immune response was noted in all separate formulations of vaccine reported, among healthy adults, 8-10 days after a single dose of vaccine, suggesting that one dose of vaccine may convey adequate immunity among adults. Adverse events were localized, similar to seasonal influenza vaccine. Clinical trials among children and pregnant women are expected in upcoming weeks. DHMH awaits CDC recommendations regarding vaccine dosing, as this will have important implications for vaccine distribution and for provider vaccination planning. For more information: http://h1n1.nejm.org/.

Update on 2009 H1N1 Treatment and Prophylaxis Guidelines
CDC has issued updated guidelines on influenza (both seasonal and 2009 H1N1) antiviral treatment and chemoprophylaxis. These guidelines reflect concern regarding the ongoing development of antiviral resistance. Treatment is recommended for all hospitalized patients with confirmed, probable or suspected influenza, and treatment should be empirically initiated on all those with presumptive influenza at higher risk of complications (children < 2 years, elderly, pregnant women, and those with chronic medical conditions). Reliance on clinical judgment, rather than laboratory confirmation, is crucial, given the limited availability and the operational delay in laboratory results. Treatment should be initiated within 48 hours of symptom development for optimal response, although antivirals are recommend for all hospitalized patients regardless of symptom duration. Negative rapid antigen influenza tests do not rule out influenza (10-70% sensitivity)( http://www.cdc.gov/h1n1flu/guidance/rapid_testing.htm). CDC has placed emphasis on early treatment as an alternative to chemoprophylaxis after a suspected exposure in order to minimize widespread antiviral use. See: http://www.cdc.gov/h1n1flu/recommendations.htm

DHMH alerts providers to those patients most vulnerable for hospitalization and death. CDC reports highest 2009 H1N1 childhood mortality rates among youth with cerebral palsy and other neurologic/develepmental disorders, as well as those with asthma and diabetes mellitus. Pregnant women are disproportionately vulnerable, especially in the third trimester. Finally, higher mortality rates observed most frequently among adults with diabetes mellitus, chronic pulmonary diseases and other underlying medical conditions. Discussing, in advance, an influenza treatment/management plan with such patients may be of utility.

Maryland DHMH thanks the medical community for its continued partnership during this extraordinary public health event.


Page updated: 09/16/09

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Contact Information

Mary M. Newman, MD, FACP,
Governor, Maryland Chapter

Maryellen Woodward
920 Trinity Street
Baltimore, MD 21202
Chapter Administrator
Office: 410-332-8444
Fax: 410-354-6732
E-mail: mew4work@aol.com