Michael T. Osterholm is Regents Professor and the director of the Center for Infectious Disease Research and Policy at the University of Minnesota. Ezekiel J. Emanuel is vice provost for global initiatives at the Perelman School of Medicine at the University of Pennsylvania and co-director of the Healthcare Transformation Institute. Both were members of the Covid-19 Advisory Board for the Biden-Harris transition.

The current omicron surge represents one of the greatest public health challenges not only of the pandemic but also of our lifetime. To deal with the surge over the next six to eight weeks, policymakers need to plan for the impact of what could be 1 million cases a day of new infections in the United States.

Such planning involves being realistic about the effectiveness of vaccination at this point; taking immediate steps to improve public health messaging, data collection and the availability of drug therapies; and doing whatever is possible to ameliorate the potentially devastating consequences for our health-care system.

Vaccines remain the best tool we have available for reducing the risk of symptomatic disease, hospitalization and death, and convincing more people to be vaccinated and obtain booster shots is imperative. But the reality is that most doses administered over the next few weeks will have little impact on the overall trajectory of this immediate surge. It takes 10 to 14 days for even a third dose to increase immune protection. For those receiving their first or second doses, there may be some limited protection provided against severe illness or death, but the window of time to act is closing quickly.

Likewise, masks can be helpful, but only if they are high-quality and used routinely. This means non-fraudulent N95, KN95 or KF94 respirators, all of which have satisfactory filtration efficiency. Cotton or surgical masks are more for show than effective protection, especially against omicron. Public health messaging is essential, not only on the benefit of masking but also on what constitutes effective masking.

Testing represents another problem area. For one thing, we cannot rely on over-the-counter tests for omicron. Many people, including those fully vaccinated, are negative according to antigen tests days into their illness — but positive according to PCR tests. With the public using antigen tests every day and relying on their results before gathering with family, going to work or visiting public settings, the National Institutes of Health and the Food and Drug Administration must immediately research the performance of available rapid tests and advise people on their reliability and best practices for using them during this surge.

In addition, the inadequacy and unavailability of reliable testing means that data on omicron cases in the United States is incomplete and will be unreliable for several weeks. Most positive cases picked up by over-the-counter rapid tests are unlikely to be reported. And bottlenecks created by heightened demand for PCR testing means many cases will go untested and unreported. Pronounced increases in omicron cases will likely overwhelm reporting resources at state and local health departments, resulting in backlogs. As a result, instead of focusing on case counts to prognosticate about omicron, policymakers should follow more reliable metrics, particularly the number of hospitalized patients who are receiving oxygen.

Another area of urgent concern is that we have too few therapies to dent the surge. The two main monoclonal antibody cocktails appear ineffective against omicron. Meanwhile, a third monoclonal that retained effectiveness against omicron is in very short supply. Ditto for the much-heralded covid-19 oral drugs. There are less than 180,000 doses of the Pfizer drug, and it takes months to manufacture. These therapies must be rationed and allocated to those most likely to suffer severe cases: the elderly, younger patients with comorbidities and the immunocompromised. Expect shortages of these therapies in the next few weeks.

Finally, and perhaps most alarmingly, we must brace for the possible catastrophic impact of the omicron surge on the U.S. health system. The weakest link is not the number of hospital beds but the availability of highly trained workers. Approximately 9.8 million doctors, nurses and high-level medical technicians are employed throughout the country. It is possible that 10 or even 20 percent of health-care workers could be infected by omicron in the next eight weeks, as has been reported in South Africa.

Losing that many health-care workers from a system already severely strained by staff shortages would be an enormous challenge. Even with the Centers for Disease Control and Prevention allowing shorter isolation and quarantine periods to help mitigate risk, covid-related absences won’t be addressed by providing hospitals with a thousand more Defense Department health-care workers. Omicron has already caused wide-scale disruptions across the airline industry, in sports leagues and among essential workers. State and local officials must put in place crisis-management plans to account for a 20 percent reduction in the health-care workforces.

To ignore these issues puts our entire country in peril. The time to act is now.