Experts say many familiar viruses, like respiratory syncytial virus (RSV), rhinovirus, adenovirus, human metapneumovirus, influenza, and parainfluenza, are acting in unfamiliar ways. RSV and the flu are usually seen in the winter months, but cases are spiking now. The rhinovirus, the cause of the common cold, is sending people to the hospital.

Researchers are trying to figure out what part of the viral shifts result from behavioral changes, such as stay-at-home orders, masking, and social distancing, versus any evolutionary advantage SARS CoV-2 may have over its microscopic rivals.

Epidemiological experts indicate the shift in seasonality is explained by our lack of recent exposure to common viruses, making us susceptible to their return. The safety measures used to reduce exposure to Covid-19 also limited our exposure to other viruses. If your body doesn’t get exposed to a virus regularly, it may not be able to protect you as well as it usually does, leading to out-of-season surges and surprisingly dangerous infections for some individuals.

On the other hand, the new virus, SARS Cov-2, may be restricting the spread of infections of its more common rivals through interactions with them. One example is the drop in flu cases in January. Experts are trying to figure out if it was caused by people staying away from each other as omicron spread or if the coronavirus pushed aside its more common rival through some other method.

As experts are examining how Covid-19 is affecting other viruses, there’s some good news for parents of very young children. Last Friday, the Food and Drug Administration (FDA) announced that Moderna’s vaccine for children 6 months to 5 years old is safe and effective. On Sunday, the agency also confirmed that the vaccine made by Pfizer BioNTech is effective and didn’t raise safety concerns.

These analyses were released before a meeting of the agency’s independent experts to consider the request for emergency use authorization for both vaccines. The meeting is scheduled for tomorrow. If the agency approves them and the Centers for Disease Control and Prevention (CDC) signs off, the shots could be available beginning next week.

The FDA made clear the importance of these vaccines in a statement on Sunday, “deployment of the vaccine for use among children 6 months through 4 years of age will likely have a beneficial effect on Covid-19 associated morbidity and mortality in this age group.” Given the uncertainty of the pandemic and the viral transmission that will continue to occur in the months ahead, this is especially vital.

Another significant announcement happened on Friday with the CDC stating that international travelers won’t need to show proof of a negative Covid-19 test before getting on flights headed to the U.S. After reviewing the science and data, the organization found that the requirement is no longer necessary.

The declaration stated, “CDC has determined that travelers have access to tools (e.g., vaccines, therapeutics, and recommended prevention measures) and guidance that allow travelers to make informed choices about the use of pre-departure testing and other prevention measures.”

However, the agency urges individuals to test before and after travel and after any known exposure to a person with covid-19. In addition, travelers who aren’t U.S. citizens, U.S. nationals, lawful permanent residents, or traveling to the United States on an immigrant visa will still need proof of vaccination before boarding their flight.

The CDC will reevaluate the decision in 90 days and reinstate the requirement, if needed, based on any new information available.