New Jersey now has more than 4.5 million residents who are fully vaccinated but the state Health Department reports about 8% of people who get their first Pfizer or Moderna shot never bother to show up for the second one.

Dr. Stanley H. Weiss, a Rutgers University epidemiologist and professor at the Rutgers Medical School, said the second dose of the mRNA vaccines give a 15-fold boost in the antibody level.

He said the first dose of vaccine provided 50 to 70% protection against the original COVID virus.

“But you now take into account the variants, which are somewhat more resistant, then the higher level of protection afforded by the second dose can be extremely important," he said.

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National COVID expert Dr. Anthony Fauci has estimated one dose of Pfizer or Moderna is about 30% effective in stopping the emerging Delta variant from India. After the second dose, protection rises to about 88%.

Weiss said the second dose “not only boosts the antibody levels, but boosts the innate immune system with cellular memory," which can play an important part in the body’s ability to fight off infection.

While the first shot gets the body ready to begin to develop reactivity to the foreign substance, the second dose quickly revs up the immune response.

He said the two-shot regimen is highly effective but with the continued circulation of different variants “we may need to be able to boost the immune system further , that would mean giving another dose of vaccine sooner than we would otherwise have to.”

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