health officials on Monday said there is no evidence yet to back concerns that a  variant first detected in the city threatens to reduce efficacy, leads to reinfection, or inflicts more severe disease.

The comments by the city health commissioner, Dr. Dave Chokshi, and senior advisor for public health, Dr. Jay Varma, follow concerns made over the weekend by former U.S. Food and Drug Administration (FDA) commissioner, Dr. Scott Gottlieb. Gottlieb told CBS’ “Face the Nation” it was unclear whether the B.1.526 variant was behind surging infections in parts of Brooklyn, Queens and Staten Island where the positivity rate is nearing 15%.

Gottlieb noted the New York variant shares a mutation with a concerning variant first detected in South Africa, which has shown to diminish, with documented of in previously infected individuals — albeit rare, though likely undercounted.

The city health commissioner said the New York variant appears to be “more infectious than other strains”, but there isn’t enough information to answer questions regarding increased virulence, vaccine efficacy and reinfection.

“We do not yet have enough information to be able to answer those questions definitively,” Chokshi said, later adding, “thus far we do not have any evidence that indicates that it causes more severe disease, or leads to reinfection or will reduce the effectiveness of vaccines but we will continue to investigate this and keep the public updated on our findings.”

Gottlieb pinned the uncertainty to under surveillance, or insufficient sequencing of cases, especially among those vaccinated or previously infected. He said officials need to start sequencing cases “much more aggressively,” though city health officials attempted to assure the public Monday that they are in fact “carefully” analyzing the data, per Chokshi.

Varma also defended city officials’ efforts in examining the data.

“There is concern absolutely that some variants, including the strains that are now more common here in New York City, may be less responsive to vaccines or you have less protection from prior infection,” Varma said. “We have not seen that so far in our data, we have been analyzing it continuously…we have been looking very aggressively and actively…”

Nevertheless, officials say the same mitigation measures to prevent infection remain the same; wear masks, practice proper distancing, maintain hand hygiene, get tested frequently and accept the first vaccine that becomes available.

Citywide coronavirus cases, hospitalizations and deaths are all declining, according to city . A seven-day average for daily infections reports 2,475 cases as of March 17, compared to a January peak topping 6,000.