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H1N1 Vaccine: The Latest

Friday, October 29, 2010 // Uncategorized

10/1/2009 8:29:33 PM

Here is the latest news on H1N1 vaccine from two sources.  The first is from The Medical Letter:

The Medical Letter®

On Drugs and Therapeutics

Published by The Medical Letter, Inc. • 1000 Main Street, New Rochelle, NY 10801 • A Nonprofit Publication

Volume 51  (Issue 1322)

October 5, 2009

H1N1 Vaccine for Prevention of Pandemic Influenza

The FDA has licensed 4 new monovalent vaccines for prevention of respiratory illness caused by a new influenza A H1N1 virus that appears to be derived from a swine strain. The 5th vaccine should be licensed soon. All of these vaccines are expected to become available in October. An intranasal formulation is expected in the first week of October.

THE DISEASE — The signs and symptoms of this  H1N1 infection have been similar to those of the usual seasonal disease, except that diarrhea and vomiting have been more common and most hospitalizations have been in persons <65 years old (REF 1).

SUSCEPTIBILITY — Serologic evidence suggests that the majority of the population less than 60 years old is susceptible to infection with this H1N1 strain (REF 2). Trivalent seasonal vaccination is unlikely to provide protection (REF 3).

FORMULATIONS — The manufacturers of the pandemic vaccine are the same as those of the seasonal vaccine. The H1N1 monovalent vaccine is being prepared using the same manufacturing process used to prepare the seasonal vaccine. Like the trivalent seasonal influenza vaccine, the monovalent pandemic influenza vaccine will be available in an inactivated intramuscular and a live attenuated intranasal formulation. Both the inactivated and live monovalent vaccines will contain antigens from the A/California/07/2009-H1N1 strain. According to the CDC, this strain is antigenically similar to the currently circulating virus.

PRIORITY GROUPS — The US Advisory Committee on Immunization Practices (ACIP) recommends prioritizing available doses of the monovalent vaccine to 5 groups identified as being at highest risk for infection or complications: pregnant women (who should receive inactivated vaccine); persons who live with or provide care for infants <6 months of age; healthcare and emergency medical services personnel; children and young adults aged 6 months-24 years; and persons aged 25-64 years old with medical conditions that put them at risk for complications. After these groups have been vaccinated, the vaccine should be offered to healthy persons 25-64 years old before those >65 years old (REF 4).

In the event that the vaccine supply is not sufficient to cover even the priority groups, vaccine campaigns should preferentially target pregnant women (REF 5) and care providers of infants <6 months of age; healthcare and emergency medical services personnel who have direct contact with patients or infectious materials; children 6 months-4 years old; and children and adolescents 5-18 years old with medical conditions that put them at risk for complications (REF 4). As with seasonal vaccination, the new vaccine is not recommended for infants <6 months old, but infants born to immunized women may be protected by maternal antibodies.

EFFICACY — In one study in adults, a single IM dose of H1N1 vaccine produced antibody levels expected to be protective within 14 days (REF 6). In an unpublished study in children, according to Medical Letter consultants, one IM dose produced antibody levels expected to be protective in a majority (76%) of children aged 10-17 years old, but in fewer of those <9 years old (36% of 3-9 year-olds; 25% of those 6-35 months old).

ADVERSE EFFECTS — The adverse effects of the H1N1 vaccine are expected to be similar to those of the seasonal trivalent vaccine (REF 7).

DOSAGE AND ADMINISTRATION — The dose of the inactivated H1N1 vaccine for patients >3 years old is 0.5 mL IM. Children 6-35 months old should receive 0.25 mL IM. The dose of the live, attenuated intranasal vaccine, which is recommended only for patients 2-49 years old, is 0.2 mL. Patients >10 years old need only one dose of either vaccine; those <9 years old should receive 2 doses about a month apart. Although studies are incomplete, either the live or inactivated H1N1 vaccine can probably be given at the same time as the inactivated seasonal vaccine without loss of efficacy. The live seasonal vaccine can also be given with the inactivated H1N1 vaccine. The two live vaccines should not be given together until studies are completed that demonstrate immunogenicity when both are given at the same time.

CONCLUSION — The monovalent H1N1 vaccine for prevention of pandemic influenza is prepared in the same way by the same manufacturers as the usual seasonal vaccine. Pregnant women, people who live with and provide care for infants <6 months old, all persons 6 months-24 years old, persons 25-64 years old with illnesses that increase their risk of influenza complications, and healthcare workers should receive it first.

And from the Texas Department of  State Health Services:

News Release
September 30, 2009

Initial H1N1 Flu Vaccine Supply to Trickle In

Texas Department of State Health Services officials report that the amount of H1N1 flu vaccine available for the state over the next few weeks will be low and are urging the public and health care providers waiting for it to be patient.

“We’ve been told that we’ll have about 15 million doses for Texas after all is said and done, but it won’t be available all at once,” said Dr. David Lakey, DSHS commissioner. “The vaccine will trickle in week to week, especially at first. It’s a fluid situation driven primarily by how much vaccine the manufacturers produce each week.”

He said some 3.4 million doses of the vaccine had been projected for Texas by mid-October, but the latest estimates are that no more than 1.7 million doses will be available by then. Weekly allotments are expected to be larger after mid-October.

Some 12,000 doctors and other health care providers in Texas have signed up to provide the vaccine.

Starting this week, the U.S. Centers for Disease Control and Prevention will tell DSHS and other states’ health departments how much vaccine is available for them to order for the week. DSHS then tells the CDC where to send it based on provider registration information, priority groups, vaccine formulation, geography and other factors. It may be one to two weeks later before that vaccine is in the hands of providers.

All of us will have to be patient and flexible as we meet this challenge,” Lakey said. “For example, pregnant women are one of the highest priority groups for vaccination, but the first vaccine available to us is FluMist. Pregnant women should not receive FluMist.”

He said the first week’s allocation of about 237,000 doses of FluMist will go to registered providers to give to children 2 and 3 years of age. Children are another high priority group.

Lakey said the total of 15 million doses should be enough vaccine to meet anticipated demand in Texas but that it could be late January before all doses are received. He reminded Texans to get the seasonal flu shot, cover coughs and sneezes, wash hands often and stay home if sick.

I will be at a medical meeting for a few days.  I’m going to take my patient list and try to prioritize the patients that are at high risk.  I still don’t know how many doses of the vaccine that I will receive and when (if?) I will receive them.

Stay tuned.

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