如同新冠肺炎病例继续增加在美国，东北部似乎正在推动这一增长。
每10万人中七天病例率最高的五个州中有四个在东北部。据统计，在七日利率最高的10个州中，有7个州位于东北部数据来自疾病控制和预防中心。
罗德岛州目前的7天病例率最高，为每10万人172.4例。这比每10万人59.4例的全国比率高出近三倍。
CDC的数据显示，截至周五，这个海洋州的平均每日病例数在两周内增加了53%，从每天170例增加到每天260例。
其他东北部的州包括佛蒙特州、纽约州、新泽西州、缅因州和康涅狄格州。
特别是纽约和新泽西平均每日病例疾病预防控制中心的数据显示，增加了64%。
专家表示，病例增加的原因之一是BA.2的传播，ba . 2是原始omicron变异体的子变异体，传播性更强。
在东北部，BA.2占已进行基因组测序的新冠肺炎病例的84%以上，比该国任何其他地区都多，根据疾病控制中心的说法。
华盛顿大学健康指标和评估研究所的流行病学家Ali Mokdad博士告诉ABC新闻，早期证据表明，在前一波感染原始omicron变种的人现在可能对BA.2有一定的免疫力。
他表示，那些能够更好地控制早期病例的州现在可能更容易受到感染。
“那些在控制感染方面做得很好的州，大多数在东北部和西部，现在更容易感染BA.2，”他说。
穆克达德使用该研究所的数据对缅因州和佛罗里达州进行了比较，该研究所预测了全国的新冠肺炎病例。
“我们估计，截至4月4日，缅因州54%的人至少被感染过一次，”他说。“所以，我们估计60%是免疫的。我们估计，截至4月4日，佛罗里达州87%的人至少感染过一次。我们估计80%是免疫的。”
专家说，东北部各州病例增加的另一个原因是口罩和疫苗需求的提高。
田纳西州纳什维尔范德比尔特大学(Vanderbilt University)预防医学和传染病教授威廉·沙夫纳(William Schaffner)博士告诉美国广播公司新闻网(ABC News)，“BA.2不仅传播性极强，而且现在，根据疾病预防控制中心的指导方针，许多人都不戴口罩，不保持社交距离，去参加拥挤的室内和室外活动。”“期待夏天的到来...人们渴望见到家人和朋友，并再次从事接近正常的活动。”
斯潘塞·普拉特/盖蒂图片公司
上，人们走过扬基体育场外的新冠肺炎疫苗试验场...
然而，专家警告说，随着一些州改变他们的新冠肺炎病毒检测策略，真实的病例数可能会更高。
2月下旬，罗德岛州卫生部宣布，从3月7日开始，州立检测站将不接受无症状患者，除非他们与病毒检测呈阳性的人有过密切接触。
该部门在一份声明中说:“在罗德岛州的国营检测点，将检测重点放在有症状的人和密切接触者身上，将确保检测结果呈阳性且符合治疗条件的人能够迅速接受治疗。”新闻稿。
沙夫纳说，他预计在未来几周内，东北部病例的增加将导致中西部、南部和西部病例的增加。
“这让人想起了美国COVID的开端，”他说。“东北部领先于全国其他地区;在COVID病毒蔓延到该县其他地方之前，他们在相当长的一段时间内受到了最多的感染。所以，也许这是一点点历史重演。”
然而，医生重申，未接种疫苗的人患严重疾病和死亡的风险最高，并强调了接种疫苗和加强免疫的重要性。
COVID-19 cases rising in Northeast, partly fueled by BA.2, experts say
AsCOVID-19 cases continue to tick upin the United States, the Northeast appears to be fueling the increase.
Four of the five states with the highest seven-day case rates per 100,000 are in the Northeast. In the 10 states with the highest seven-day rates, seven are Northeastern, according todatafrom the Centers for Disease Control and Prevention.
Rhode Island currently has the highest seven-day case rate at 172.4 cases per 100,000 people. This is nearly three times higher than the national rate of 59.4 cases per 100,000 people.
As of Friday, the Ocean State has also seen its average daily number of cases increase 53% over a two-week period from 170 per day to 260 per day, CDC data shows.
Other Northeastern states seeing increases include Vermont, New York, New Jersey, Maine and Connecticut.
In particular, New York and New Jersey have seen theiraverage daily casesincrease by 64%, the CDC data shows.
Experts said one of the reasons for the rise in cases is the spread of BA.2, a subvariant of the original omicron variant that is more transmissible.
In the Northeast, BA.2 accounts for more than 84% of COVID-19 cases that have undergone genomic sequencing, more than any other region in the country,according to the CDC.
Dr. Ali Mokdad, an epidemiologist with the University of Washington's Institute for Health Metrics and Evaluation, told ABC News that early evidence suggests people who were infected with the original omicron variant during the previous wave may now have some immunity against BA.2.
He suggested states that were able to have better control of cases earlier may currently be more vulnerable to infections.
"States that did a good job controlling infections with mandates, most in the Northeast and West, are more susceptible now with BA.2," he said.
Mokdad compared Maine and Florida using data from the institute, which projects COVID-19 cases around the country.
"We estimate that 54% of people in Maine have been infected at least once as of April 4," he said. "So, we estimate that 60% are immune. We estimate that 87% of people in Florida have been infected at least once as of April 4. We estimate that 80% are immune."
Another reason Northeastern states may be seeing case increases is due to the lifting of mask and vaccine requirements, the experts said.
"Not only is BA.2 extraordinarily transmissible, but now, consistent with CDC guidelines, many people are going to crowded indoor events and outdoor events without wearing a mask and not social distancing," Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University in Nashville, Tennessee, told ABC News. "In anticipation of summer ... people are eager to see family and friends and engage in near-normal activities again."
However, the experts warned the true number of cases could be even higher as some states shift their COVID-19 testing strategy.
In late February, the Rhode Island Department of Health announced that -- starting March 7 -- state-run testing sites would not accept asymptomatic patients unless they had been in close contact with a person who tested positive for the virus.
"Focusing testing efforts at Rhode Island's state-run testing sites on people who are symptomatic and people who are close contacts will ensure that people who are positive and eligible for treatment can be quickly connected to treatment," the department said in anews release.
Schaffner said he expects that the rise of cases in the Northeast will be followed in the next few weeks by increases in the Midwest, the South and the West.
"This is reminiscent of the very beginning of COVID here in the United States," he said. "The Northeast led the rest of the country; they had the most infections for quite a period of time before the COVID virus spread to the rest of the county. So perhaps this is a little bit of history repeating itself."
However, the doctors reiterated that unvaccinated people are at the highest risk of severe illness and death from BA.2 and stressed the importance of getting vaccinated and boosted.
