Flu shot imageAt the start of every Flu season any news of a vaccine shortage sends public health officials and health care workers scrambling. The 2004-5 flu vaccine shortage was no ordinary shortfall. Approximately half the US supply, 48 million doses, could not be delivered because of manufacturing problems.

The shortage forced the Centers for Disease Control and Prevention (CDC) to reconsider who is at most risk for flu complications, and who should get priority for receiving one of the too-few flu shots. While the flu vaccine is one of many possible immunizations, the recent shortage highlights the need to understand how the supply of vaccines is balanced against demand in this country.

Understanding the Supply

The flu vaccine shortage is probably the most widely known, but there have been other vaccine supply problems. In 2001, the US experienced shortages of eight of the 11 routinely administered childhood vaccines, causing a shuffling of immunization schedules and delayed immunizations. The affected vaccines included:

By the summer of 2002, most of the supply of these vaccines had been replenished. The question remains as to why it happened in the first place.

The vaccine supply problem is multifaceted. Part of the problem is that there are fewer pharmaceutical companies in the vaccine business than in the treatment drug industry. Thirty years ago, there were 25 companies producing vaccines in the US. Today, there are five.

Fewer pharmaceutical companies are interested in producing vaccines because it is not as profitable. Vaccines are given once or just a few times to an individual, whereas a drug may be needed daily. Vaccines require fairly long research and development time. The government purchase of the majority of childhood vaccines, at a significant discount, leave vaccines less profitable than other products. Mergers among pharmaceutical companies have also left fewer companies available to produce vaccine. Many vaccines, including tetanus and polio, are manufactured by only one company, so if they have production problems, there is no backup supplier.

Understanding the Demand

The CDC’s Advisory Committee on Immunization Practices (ACIP) is responsible for recommending who should receive what vaccine at what age. Children, who make up the largest group of vaccine recipients, receive 8–9 different vaccinations, some in multiple doses, between birth and 18 years. As adults, a tetanus-diptheria booster is necessary every 10 years and a yearly flu vaccine is commonly recommended. Pertussis booster vaccines are also becoming available. Adults 65 years and older should receive a one-time pneumococcal vaccination.

Vaccines can be purchased privately from the manufacturer or through the CDC’s National Immunization Program. The National Immunization Program purchases vaccines directly from the manufacturers. In fact, the government spends more than $1 billion on childhood vaccines alone, and negotiates significant price discounts because of its large volume orders. The government-purchased vaccines are then distributed to state programs, public health clinics, and private health care providers servicing disadvantaged patients. About 56% of childhood vaccines are purchased through the government; the rest are purchased privately.

In deciding how much vaccine to buy, the government relies on states and other parties to estimate how much they will need for a calendar year and divide it into a monthly number, assuming that some vaccines are more seasonal than others. Vaccine demand estimates are based upon historical data but take into consideration average yearly increases and the current population that falls within the ACIP recommendations.

A Balancing Act

Balancing vaccine supply against demand is no easy task, as the past flu vaccine shortage has demonstrated. But what’s the solution? Giving less vaccine to more people may turn out to be one possibility. A study recently published in the New England Journal of Medicine studied the effectiveness of smaller flu vaccine doses in conferring immunity. The researchers studied 100 healthy adults ages 18-40 who were given either a normal flu vaccine dose through an intramuscular shot, or one-fifth the dose intradermally (in the skin). The researchers found that the smaller dose was similar or better in terms of immunity provided than the regular dose. While the results are promising, the study’s authors note that further research is necessary.

In addition, at the request of the CDC, the Institute of Medicine (IOM) studied the current vaccine system to develop recommendations on improving vaccine access and availability. The IOM study recommends mandating that both private and public health plans cover all vaccinations recommended by the ACIP, and that the government’s role change from purchasing vaccines to reimbursing health insurance plans for the vaccines. Finally, it recommends that a voucher plan be instituted for all uninsured individuals to ensure that everyone is vaccinated as recommended. The cited benefits of this system include higher immunization rates, a stabilized vaccine supply, manufacturer incentives for new vaccines, and fewer delays or shortages.

Public and Individual Health

Vaccines are one of medicine’s greatest achievements. Immunizations benefit not only the individual, but also society at large by preventing the spread of disease. The cost savings are real—from reduced medical costs to lengthening of life to improved productivity. And yet, somehow the supply and demand of vaccines often seem to be out of balance. Whether the solution is giving less vaccine to more people or offering incentives to manufacturers, it is clear that finding the right balance is important.

Fortunately, spurred in part by the threat of an emerging influenza pandemic, US vaccine production is on an upswing. Most experts predict that—barring unforeseen problems with production—the current vaccine supply should be adequate to meet demand.