Credit: (AP Photo/Rebecca Blackwell)

Editor’s Note: NJ Spotlight News is marking the second anniversary of the arrival of COVID-19 in New Jersey by focusing on how the disease changed our lives and what life looks like now. In this story, we look at the data for the infection rate and case numbers in New Jersey compared to other states. You’ll find all our pandemic-related stories here.

New Jersey was one of the first states on the East Coast to experience the COVID-19 pandemic.

The first case of COVID-19, the disease caused by the novel coronavirus, was confirmed in New Jersey on March 4, 2020, although there may have been some cases even earlier. A month later, some 50,000 New Jerseyans had been infected and the number of positive tests exceeded 4,200 a day, the highest number until around Thanksgiving.

That first holiday season saw concerningly high case numbers, but they were nothing compared to the tens of thousands of new daily cases post-Christmas 2021. On Jan. 7 of this year, the state reported close to 38,500 new cases.

Not every state experienced viral waves — due to the presence of variants or the relaxation of restrictions or both — at the same time, but every state has seen large numbers of cases. The graphic below shows the number of cases per 100,000 residents in each state from the start of the pandemic through Feb. 27.

Since quite early in the pandemic, health officials have said that more people likely have had COVID-19 than test results show because not everyone has been tested and some people may have been asymptomatic. The Centers for Disease Control and Prevention has been working with laboratories to get a better sense of the prevalence of the infection and recently released data showing that perhaps twice as many people have been infected by COVID-19 than testing data shows.

The CDC’s antibody seroprevalence survey, which relies on blood tests that look for evidence of a past infection, estimates there were 140 million COVID-19 infections in the country through late January, compared to about 74 million positive tests. The estimate is based on samples that are weighted and reported with a margin of error for the nation and all but four states, for which there was not enough information.

For New Jersey, the survey estimated that 51% of the population has had a COVID-19 infection, with the number potentially as low as 48.3% or as high as 53.5%. That translates into some 4.5 million previous infections, which is more than double the 2.17 million positive test results for both PCR blood tests and rapid antigen testing that have been recorded in the state.

CDC officials stress that evidence of a prior infection from the coronavirus does not necessarily protect a person from a future infection and they continue to say that a full course of vaccine with a booster is the best defense against the virus.