A version of this story appeared in the March 2 edition of CNN’s Coronavirus: Fact vs. Fiction newsletter. Sign up here to receive the need-to-know headlines every weekday.

CNN  — 

There have rarely been so many positive signs at any stage throughout this pandemic. A third Covid-19 vaccine is being rolled out across the United States. Millions of people are getting their shots. Fewer Americans are being hospitalized. Yet public health experts are pleading loud and clear: This is absolutely not the time to let your guard down.

The US is facing a very real risk of losing all its recent gains in the battle against the virus as highly contagious variants take advantage of Americans getting lax with safety measures.

There are worrying signs already. While US Covid-19 cases and hospitalizations were trending downwards for several weeks, they are still alarmingly high. And that downward trend now seems to have stopped. The most recent seven-day average of new cases shows an increase of just over 2% compared to the prior week , Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said yesterday. A similar increase was reported in the most recent seven-day average of deaths, she added.

“Please hear me clearly,” Walensky said. “At this level of cases with variants spreading, we stand to completely lose the hard-earned ground we have gained. These variants are a very real threat to our people and our progress.”

Dr. Zeke Emanuel, who was a health adviser to the Obama White House and a member of the Biden Transition Covid-19 Advisory Board,said Americans need to hold on to the strict safety measures for another two or three months. “We should not ease up, allow indoor dining, big groups … getting rid of mask mandates,” he said.

The World Health Organization (WHO) raised a similar concern yesterday, after the number of new cases globally rose last week for the first time in seven weeks. WHO Director General Tedros Adhanom Ghebreyesus said the increase was “disappointing but not surprising,” adding that the agency is working to better understand increases in transmission.

“Some of it appears to be due to relaxing of public health measures, continued circulation of variants and people letting down their guard,” Tedros said. “Even as vaccines continue to roll out, we urge all governments and individuals to remember that vaccines alone will not keep you safe.”

YOU ASKED. WE ANSWERED

Q: Is testing for Covid-19 still important?

A: Covid-19 testing numbers are dropping in the US. And that’s bad news. Without testing, there’s no way to keep track of where the pandemic is headed and whether vaccines are working. And there’s no way to make use of one of the most important tools for fighting infectious diseases: contact tracing.

We asked CNN Medical Analyst Dr. Leana Wen to weigh in. Her top advice: “Take the vaccine that you are offered. All three vaccines are safe and effective. Think about other vaccines we take, like for the flu vaccine. Most of us don’t ask which company manufactures it. We just care that it works.”

Send your questions here. Are you a health care worker fighting Covid-19? Message us on WhatsApp about the challenges you’re facing: +1 347-322-0415.

WHAT’S IMPORTANT TODAY

Vaccines dramatically cut risk of hospitalization in over 80s, real-world data shows

A single dose of either the Pfizer-BioNTech or Oxford-AstraZeneca vaccines reduces the risk of hospitalization from Covid-19 by more than 80% in people aged over 80, new data from Public Health England shows.

The effect was seen three to four weeks after vaccination. People aged over 70 were also shown to have up to 61% protection against symptomatic disease from the Pfizer-BioNTech shot and up to 73% from the Oxford-Astra-Zeneca vaccine.

The UK has administered Covid-19 shots to more than 20 million people, with campaigns first targeting the over-80s who are most vulnerable to the disease. The new data supports the country’s decision to use both the Pfizer-BioNTech and Oxford-AstraZeneca vaccines at a time when other countries in Europe showed concern about using the AstraZeneca shot in older people. Meera Senthilingam repor

Unable to cope with new variants, Brazil’s hospitals reach breaking point

Intensive care units are nearing their limits across Brazil, as health experts and state officials beg the government to impose strictermeasures to reduce coronavirus transmission. The country is struggling to control the new, more infectious coronavirus variants. “The mutated virus has three times more contamination capacity, and the speed can surprise governors in terms of structure and support,” said Health Minister Eduardo Pazuello. This is the reality we have today in Brazil.”

UK hunts for person infected with Covid-19 variant

British health officials are racing to track down a person who has been infected with a Covid-19 variant first identified in the Brazilian city of Manaus. The person is one of six cases of the P.1 variant in the UK. The variant carries a pattern of mutations that appears to make the virus more easily transmitted. The unidentified individual did not complete a registration card associated with their test so officials are not able to easily find them.

ON OUR RADAR

TOP TIP

While many Americans are staying home for their own safety during the pandemic, home can be the most dangerous place for domestic violence victims. The usual places that victims escaped to in the past are not always available now.

Domestic violence incidents rose in the US by about 8.1% after the imposition of pandemic-related lockdowns, according to an analysis by the National Commission on Covid-19 and Criminal Justice.

But help is available. If you or someone you know is being affected by domestic violence, call the National Domestic Violence Hotline / 1-800-799-SAFE (7233) / TTY 1-800-787-3224. A worldwide list of directories is provided by UN Women. You can also find a list of national agencies on The Pixel Project.

TODAY’S PODCAST

“When you’re an inch away from all of your aspirations being taken away from you and the Games maybe even being completely canceled, it’s heartbreaking.” – Sandi Morris, 2016 Olympic silver medalist

“These are portraits of people who are just taking a break being between patients at work or taking a breather. And I wanted to capture that moment and that emotion in their eyes.” – Jayashree Krishnan, a Seattle-based artist.