Two worrisome variants make up over 70 percent of cases analyzed in N.Y.C., city officials say.

New York City health officials said Monday that infections with coronavirus variant B.1.1.7, which first appeared in the UK, have increased in every district, but slightly more in south Brooklyn, east Queens and Staten Island . The genetic analysis shows that B.1.1.7 now accounts for around 30 percent of the cases sequenced across the city.

The data, included in new maps and a report released by the city, represents the first time officials have given a zip code-level look at how worrisome variants have spread across New York and, in some cases, original versions of viruses and Clusters overtook parts of the city more than others.

The report and maps, published Monday afternoon on the city’s health department website, also show that a variant that first appeared in New York City (B.1.526) has increased even faster and is now around 45 percent of the time Cases are genetically sequenced in the city. The maps released on Monday show that while B.1.526 is found in all five boroughs, it is slightly more common in the Bronx and parts of Queens.

Overall, more than 70 percent of the genetically sequenced coronavirus cases currently prevalent in the city represent worrying variants. The data, which spans January 1 through March 27, makes up less than 5 percent of all positive test results in the City because the sequencing options remain limited. As a result, there is only one glimpse into the bigger picture of how the variants will affect each community.

New York City has been on a plateau of coronavirus cases since February. According to the city, around 3,000 to 4,000 new cases are reported every day. The prevalence of these variants is likely a primary reason why cases have not continued to decline despite rising vaccinations, the city’s health department said in the report.

Hospital admissions have declined, but very gradually, as the most vulnerable are vaccinated. Deaths also decreased, but more slowly than desired, averaging around 50 per day.

The United States has seen an exponential increase from B.1.1.7, which, according to the Centers for Disease Control and Prevention, is now the most dominant variant across the country. According to the latest estimates, this variant is about 60 percent more contagious and 67 percent more deadly than the original form of the coronavirus.

It struck Europe and helped fuel the worst outbreak in Michigan. Until recently, the rise in the variant in the U.S. was somewhat camouflaged by declining infection rates overall, prompting some political leaders to relax restrictions on indoor eating, social distancing, and other measures. The CDC’s efforts to track down the variants have improved significantly in recent weeks and will continue to grow, despite the fact that the UK, which has a more centralized health system, launched a heavily funded sequencing program last year to track the spread of the B. could .1.1.7 variant.

Vaccines appear to be effective against the variant.

Less is known about variant B.1.526, which was first documented by researchers in the Upper Manhattan area of ​​New York City last November and has since spread widely throughout the city and beyond. City officials have said the variant may be more transferable and in some parts of the city even surpasses B.1.1.7.

However, it is not yet known whether the variant has any effect on disease severity, re-infection, or the effectiveness of the vaccine. The city said it has no evidence, but is investigating these possibilities.

The city also warned Monday that the P.1 variant, first identified in Brazil, is increasing its presence, although its incidence as a percentage of total cases remains very low.

The city has not released any data or a map showing where P.1 cases have been identified. It has already been said that the variant accounted for 1.3 percent of the samples sequenced at the end of March – a total of only 24 cases of P.1. The variant maps released on Monday also excluded all postcodes where the total number of cases sequenced was less than three.

P.1 is also more transmissible than original versions of the virus, and there is evidence of bypassing immunity in both those who have previously had Covid-19 and those who have been fully vaccinated. It is widespread in South America and has occurred in many states.

The city’s report did not mention variant B.1.351, which occurs for the first time in South Africa and which can partially evade the reaction of the body’s own immune system. The city had previously reported that a total of 6 cases of B.1.351 had been sequenced.