It has been confirmed that US Defense Secretary Lloyd Austin has COVID-19. His symptoms are said to be "mild" and he will quarantine at home for the next five days, according to a statement the Defense Department published on Sunday.

The Omicron variant of the novel coronavirus is driving a surge in the number of cases across the United States. As of early this week, the cumulative number of infections had hit more than 56 million, among whom 827,700 people had died of the disease.

Although the Joe Biden administration claims it has done all it can to tame the virus, the effects have proved to be limited, and its pandemic prevention and control strategies face multiple challenges.

In the first place, some executive orders on the pandemic prevention and control the previous Donald Trump administration signed remain effective, even if some of them contradict with policies the Biden administration makes. As the Trump administration designated many industries, such as meat processing, as essential infrastructure that are not expected to suspend their operations even if the federal government decrees industries to do so to fight the virus.

Also the Biden administration's pandemic prevention and control policies are only tight on paper, and they are poorly implemented in practice. The US government has shortened the quarantine period of asymptomatic cases to only five days, and ignored infectious disease specialists' suggestion that it should be made compulsory that those people should continue to wear face masks and receive nucleic acid tests after finishing their five days of quarantine.

The implementation of testing, vaccination and pandemic protocol in the US all lag behind the requirements of the situation. That was the case during the Trump administration, and the Biden administration has not changed that.

The infighting between Republicans and Democrats has seriously affected the implementation of the Biden administration's pandemic prevention and control policies. Some public health measures the Biden administration proposed have not gained the support of the Republicans, making it difficult to obtain funding approval from Congress to put the measures into practice.

The Biden administration's mandate that businesses with more than 100 employees be vaccinated has faced stiff resistance in many Republican-run states and localities. Republicans have argued that the Biden administration did not have the authority to bypass Congress to issue such an order.

In the field of epidemic control and public health governance, the boundary of responsibility and obligation between the federal government and local governments is blurred. Some seemingly sensible federal measures, such as social distancing, mask wearing, testing and temporary lockdowns of public places, have been interpreted in many quarters as an infringement of states' rights.

If the political dilemma cannot be addressed, with about 1 million new cases appearing in the country on Monday, the worst days of the US in the pandemic are yet to come.