Vaccine making is not an easy process.
Each February experts make a decision about what type of flu vaccine to produce for the upcoming season and as you may imagine, this year's outbreak of A (H1N1) and the production of a swine flu vaccine has disrupted that schedule a bit.
And while seasonal flu vaccine is still being made, it's hard for the current vaccine producing system to shift gears fast enough, and the technology being used is not as modern as we might like.
While the first trial vaccinations are expected within a few weeks, it may not be until the end of this year that a fully tested swine flu vaccine is ready according to the World Health Organization (WHO).
An already difficult vaccine production process is made worse by the swine flu viruses being used to develop the vaccine.
It seems they're only offering half as much "yield" in egg-based production (most of today's vaccine is made this way) as what manufacturer's get when creating vaccine for the seasonal flu virus.
US health officials are said to be considering a swine flu immunization program that involves an astonishing 600 million doses. Who will administrator the vaccine, and how side effects will be tracked has yet to be determined.
The good news is that swine flu, known primarily as A (H1N1), remains a reliably mild illness and the vast majority of patients continue to recover quickly.
The virus is still susceptible to antiviral drugs, including Tamiflu, which makes these medicines ideal as a treatment option for infected patients.
On the bottom side, research does suggest that A (H1N1) causes more lung damage than the seasonal flu strain.
It's also important to know that this A (H1N1) strain is able to take the life of the young and previously healthy.
In fact, almost half of those who've died worldwide have been just that. By contrast, the seasonal flu is usually most deadly to the very young or the very old.
In a piece on the A (H1N1) flu appearing in the journal Nature, University of Wisconsin-Madison scientist Yoshihiro Kawaoka and collections took virus samples from patients infected with the A (H1N1) swine flu and looked at how they affected different animals.
In mice, ferrets and monkeys, the A (H1N1) swine flu virus brought on lung conditions that were more severe than seen in the seasonal flu. Researchers think this may explain why A (H1N1) has caused some serious cases of pneumonia in those who were otherwise healthy.
The A (H1N1) swine flu arrived in the US in the middle of April, and estimates have about one million Americans being infected though there are far fewer "confirmed" cases.
There continue to be deaths from the illness.
The Wisconsin researchers also found that A (H1N1) is closely related to the viruses that were behind the devastating 1918-1919 Spanish flu pandemic. In fact, antibodies taken from those born before 1920 recognize the current swine flu virus, not so for those born after 1920.
What worries health officials today is that the virus we know now may mutate into a more virulent and dangerous illness.
While we continue to wait for a vaccine to arrive, it's important to look back at the last large-scale government-backed swine flu vaccination campaign in 1976. In hindsight a program that earned mixed reviews.
It was an incredible mobilization of the nations health care system, although a miserable failure after a paralysis nerve disorder known as Guillain-Barre syndrome stuck 500 (and killed 30) of those who had been vaccinated.
It was not until December 1976 that federal officials appealed the program, although not before 40 million Americans were inoculated against a pandemic that in the end never materialized.
Perhaps the lessons learned from this, as well as the WHO decree that before a country can start a large-scale swine flu vaccine program the vaccinations used need to be checked for safety by regulators, will help future efforts improve on past ones.