The number of swine flu cases in the U.S. passed 100 today, and U.S. authorities said they eventually could produce enough vaccine for everyone if necessary — but that shots couldn’t begin until this fall at the earliest. Nearly 300 schools across the country were closed today as a direct result of swine flu as well.

The swine flu outbreak has penetrated over a dozen states, and even reached as far as the White House, which disclosed that an aide to Energy Secretary Steven Chu apparently got sick while helping arrange President Barack Obama’s recent trip to Mexico. They added however that the aide did not fly on Air Force One and never posed a risk to the president.

So far, the U.S. cases are fairly mild for the most part, with one death – a Mexican toddler who visited Texas with his family — unlike in Mexico where more than 160 suspected deaths have been reported. Apparently also, most of the U.S. cases so far didn’t need a doctor’s care.

Still, the U.S. is taking extraordinary precautions, including shipping millions of doses of anti-flu drugs to states in case they’re needed against what the World Health Organization has called an imminent pandemic, because scientists cannot predict what a brand-new virus might do. A key concern is whether this spring outbreak will resurge in the fall.

In terms of official Swine Flu numbers in the U.S., the CDC (Centers for Disease Control) confirms 109 cases and state officials confirm 19 more. CDC confirms: 50 in New York; 26 in Texas; 14 in California; 10 in South Carolina; two each in Kansas and Massachusetts; and one each in Indiana, Ohio, Arizona, Michigan and Nevada. State officials confirm five in New Jersey; four in Delaware; three additional cases in Arizona; two additional cases in California; two in Colorado; one additional case in Michigan; and one each in Georgia and Minnesota.

Overnight, the swine flu outbreak has spread to four more states here in the U.S., bringing the total to at least 91 cases. There is also the first confirmed U.S. death from the new virus – a 23-month old toddler from Mexico who died in a Houston hospital. The child was from Mexico City and had traveled to Matamoros on a commercial flight with his family to visit relatives in Brownsville, Texas. His symptoms reportedly grew severe, and he was taken to Houston to seek medical treatment but later died.

The four new states that are reporting Swine Flu cases are Arizona, Massachusetts, Michigan and Nevada. Texas has reported that its total has now climbed to 16 cases, while New York has 51, and California has 14.

Health and Human Services Secretary Kathleen Sebelius told reporters on her first day at work following Senate confirmation Tuesday, that “we expect to see more cases, more hospitalizations, and, unfortunately, we are likely to see more deaths from the outbreak.“

President Barack Obama said today that the growing number of cases of swine flu in the United States and abroad was “not a cause for alarm,” but he also sought to assure Americans that the U.S. Government was taking precautions to prepare for the prospect of a global swine flu pandemic.

At a previously-scheduled speech that he delivered to scientists in Washington earlier today, the President personally addressed the swine flu issue for the first time, saying “We are closely monitoring the emerging cases of swine flu in the United States. This is obviously the cause for concern and requires a heightened state of alert, but it’s not a cause for alarm. Science is more essential for our prosperity, our security, our health, our environment and our quality of life than it has ever been before. If there was ever a day that reminded us of our shared stake in science and research, it is today.”

The suspected death toll from the outbreak of swine flu in Mexico rose today to 149 persons, as health authorities cancelled all schools across that country until May 6.

Mexican Health Secretary, Jose Angel Cordova, along with other cabinet officials held a press conference earlier today in Mexico City where they disclosed the latest information that they have gathered about the swine flu outbreak that has halted many aspects of public life in Mexico and appears to be spreading.

Cordova said that since the first case of swine flu was reported, 1,995 people have been hospitalized with serious cases of pneumonia, and 1,070 of these people have since been released. He said 20 of the deaths have been confirmed as being caused by swine flu, but that just two laboratories in the country – one in Mexico City and one in the state of Veracruz – are able to confirm this new swine flu strain.