Washington, April 4 : The US is witnessing an increase in Covid-19 cases, including infections from new and emerging variants, as experts have expressed concerns about another surge amid the upcoming spring break. Covid-19 cases in the country were steadily decreasing for approximately 10 weeks, however, trends are changing, and cases have increased during the past 12 days, Xinhua news agency quoted the US Centers for Disease Control and Prevention (CDC) as saying in an update on Saturday. The current seven-day moving average of daily new cases, which stands at 62,167, increased 8.4 per cent compared with the previous seven days. Meanwhile, the seven-day average of daily hospital admissions of infected patients, which stands at 4,948, is a 4.8 per cent increase from the previous seven-day period, according to the CDC. Overall, Covid-19 deaths in the country have decreased for the past 11 weeks, except for an increase during March 27 and 28. Compared with the highest daily death peak on January 13, which was 3,379 deaths, the current seven-day moving average of 880 daily new deaths decreased 74 per cent, CDC data show. Experts are concerned about another surge of new cases and increasing variants infections as lots of people are planning travels during the spring break. The country recorded more than 13,000 infection cases of coronavirus variants as of Thursday, according to the latest data of the CDC. Among these cases, 12,505 cases were caused by the variant known as B.1.1.7, which was originally detected in Britain. There were 323 cases of the strain initially discovered in South Africa, called B.1.351, and 224 cases of the P.1 strain first discovered in Brazil. In addition, the B.1.427 and B.1.429 variants, two coronavirus strains first detected in California, are also being closely monitored by the CDC. The five coronavirus strains are currently classified by the CDC as "variants of concern", as evidence shows an increase in their transmissibility, increased hospitalisations or deaths, significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures. "These variants of concern are mutated versions of the SARS-CoV-2 virus and have the potential to cause COVID-19 to be more severe, spread more easily between humans, require different treatments, or change the effectiveness of current vaccines," the CDC said in a report. As of Saturday, more than 104 million people in the US have received at least one Covid-19 vaccine dose, according to the CDC. A total of 161 million vaccine shots have been administered by Saturday, while more than 207 million doses have been distributed across the country. Currently nearly 60 million Americans have been fully vaccinated, about 18 per cent of the whole population, according to the CDC. "The race to vaccinate people and contain the virus is underway. The actions we take today determine how long it will take to stop the virus and end the pandemic," said the CDC. The US is still the worst-hit country with the world's highest number of cases and deaths at 30,671,074 and 554,779, respectively, according to the Johns Hopkins University. /IANS