Editor's Note: (Dr. Tom Frieden, director of the US Centers for Disease Control and Prevention during the Obama administration, when he oversaw responses to the H1N1 influenza, Ebola and Zika epidemics, is president and CEO of Resolve to Save Lives, an initiative of Vital Strategies, and senior fellow for Global Health at the Council on Foreign Relations. Twitter: @DrTomFrieden.)
(CNN) Although it's possible that deadly new coronavirus variants could emerge, I'm more optimistic today than at any point since the Covid-19 pandemic began. Here's why.
Despite growing pandemic fatigue and rough weeks ahead as the Omicron tsunami recedes, we're better defended against Covid than ever. Vaccines and prior infection have steadily strengthened our collective immune defenses. We have now built up a wall of immunity -- although we have lost far, far too many people along the way to get here.
In 2020, failure to follow public health recommendations greatly increased the death toll in the United States and elsewhere. In 2021, failure to reach people with vaccination -- largely due to partisan opposition and entrenched resistance in the US, and lack of access in many countries -- had lethal consequences.
We've already lost nearly 900,000 people to Covid in the United States alone and are closing in on the grim milestone of a million American deaths. Most could have been prevented. But now, we can have the upper hand over Covid because our defenses are multilayered and strong, starting with immunity.
Based on antibody seroprevalence among people who donated blood, an estimated 94% of Americans had at least some protection against Covid back in November -- before the Omicron variant's surge hit -- through either vaccination or prior infection. Immunity against severe infection is holding up, especially for people who receive booster shots. In December, the rate of Covid-associated hospitalization was 16 times higher in unvaccinated adults than among adults who were up to date on vaccination.
Globally, 10 billion doses of lifesaving vaccines have been administered in just over a year. That's a stunning achievement, although vaccine inequity continues to cost lives and create the conditions for dangerous variants such as Omicron to emerge. Africa remains particularly vulnerable, as less than 1 in 10 people continent-wide are fully vaccinated.
We have new drugs that are highly effective at preventing severe Covid. Lab studies suggest they will work just as well against the Omicron variant as Delta. Generally, medical treatments don't have anywhere near the life-saving impact of vaccines, but they help. These pills could be a life-saver for people at high risk of severe Covid, though we must still overcome supply challenges, pair testing with early treatment and make sure there's equitable access for everyone who needs them.
Most people understand that masks work and that better masks (such as N95s) work better, and there are now more of them. Masks can stop airborne spread of whatever variant Covid throws at us. We can learn from East Asia by masking if we're sick or vulnerable, to resist not just Covid but flu and other respiratory diseases.
Although there have been bumps in the road, testing is more widely available, including rapid antigen tests that can be done at home. When Covid is spreading in our community, we can test before gathering indoors with vulnerable people or in large groups, or test if we feel sick; if infected, we can isolate at home until no longer contagious.
Genomic surveillance is another tool that we've sharpened. South Africa set a great example by warning the world about Omicron. Many countries have increased their capacity to perform robust genetic sequencing. We can stay ahead of the virus by continuing to be on the lookout.
Genomic surveillance alerted us to a new version of Omicron, termed BA.2, that's becoming more common in several countries. This Omicron subvariant has generated concern, but findings from the UK suggest that BA.2 doesn't escape immunity any more than the version we've been dealing with.
All of the above are reasons for cautious optimism, but there are wild cards. Protection from Omicron infection may not be strong or long-lasting; less severe infections often result in less lasting immunity. And although vaccine protection has held up well against severe disease, we may need additional doses to stay up to date.
Long Covid is another ongoing challenge. We don't know how often an Omicron infection leads to long Covid or how best to treat people who have the condition, although we're learning more every day and eagerly await study results from the National Institutes of Health. A new study suggests that vaccinated people who get infected are much less likely to develop long Covid, another reason to keep your vaccinations up to date.
The biggest wild card: SARS-CoV-2's ability to mutate. It's highly unlikely that Omicron will be the last variant. What's to say a deadly, highly transmissible, immune-escape variant won't arise? Frankly, it could.
But even if a worse variant emerges, we're better prepared than ever: more immunity, more vaccines, more treatments, better masks and more of them, better tests, better understanding of Covid, more sequencing. Covid doesn't have to keep dominating our lives, and with our improved defenses, we may soon be able to safely resume many activities.
Another reason for optimism? We have a unique opportunity to put public health systems in place to find, stop and prevent health threats when and where they emerge, anywhere in the world. With our partners, Resolve to Save Lives advocates for 7-1-7 as a global goal for early disease detection and response. Every outbreak should be detected within seven days, with public health authorities notified and investigation started within one day and all essential control measures established in the next seven days.
The world has a once-in-a-lifetime chance to make the world safer from health threats. The Global Fund, which last week celebrated its 20th anniversary, has made impressive progress against AIDS, tuberculosis and malaria, and it should play a key role in preventing the next pandemic.
Every country and every organization has made mistakes, and challenges remain, but we've come a long way in the past two years. The most important lesson we can learn from Covid is that we're all in this together -- that a disease outbreak anywhere is a threat everywhere.
Far, far too many lives have been lost to Covid, and it's not over yet. But we can learn the lessons from the past two years and work together to create a safer world where, instead of adding to fear of contagion, the connections among us strengthen our health, our economy and our common community.