Some teenagers who want the shots have found that the biggest obstacles are their parents who worry about side effects that have yet to emerge. Many young adults are skipping vaccination because they don't see the urgency. Vaccine hesitancy is not the only problem. In most states, Black and Hispanic people have received fewer vaccinations relative to their share of cases and their share of the total population, according to surveys by the Kaiser Family Foundation. The reasons for this disparity are innumerable, but systemic racism and income inequality play huge roles. Many marginalized groups are leery of a government that has failed them time and again. Some people have been stymied by a lack of paid leave or by transportation issues or by simple misunderstandings; for instance, not all people have been made aware that they are not supposed to be charged for shots. In Latino communities, the fear of immigration enforcement at vaccination sites looms large. In other countries, the trouble is both more straightforward and much more dire: There are simply not enough shots to go around. Part of the problem has to do with hoarding, as wealthy nations have gobbled up much of the vaccine supply. But also, vaccine makers are producing only a tiny fraction of what's needed to begin with. The result is a profound global vaccination gap. While the United States has vaccines for anyone who wants them, most other countries are still struggling to inoculate even their most vulnerable residents, including frontline health care workers and older people. In Indonesia, where the Delta variant is surging, fewer than 5 percent of residents have received any vaccine. As the second pandemic summer progresses, it will be crucial to tease these strands apart and address the roots of each one. Much of the growing mistrust of vaccines can be traced to an anti-vaccination movement that is well funded, politically connected and media savvy. Its efforts have succeeded to such an alarming degree that vaccine hesitancy ranked as one of the world's leading global health threats well before the Covid pandemic emerged. But it's important to remember that this contingent makes up a small portion of unvaccinated people. A large majority of Americans are not opposed to vaccines, only hesitant. That means they can still be won over. The Biden administration has started a multimillion-dollar campaign to dispel vaccine misinformation and educate Americans about the benefits of getting the shots.