WASHINGTON -- A pair of Senate Republicans leading the congressional investigations into Dr. Anthony Fauci released an initial batch of text messages Monday from his government-issued cellphone, shedding more light on his real-time response to the Covid-19 pandemic.

The phone contains more than 34,000 text messages and 522 voicemails, according to the offices of Sens. Rand Paul (R., Ky.) and Ron Johnson (R., Wis.), who lead committees that are conducting parallel investigations into Fauci's response to the pandemic.

Fauci had returned the phone upon retiring from government in 2022, and the Department of Health and Human Services transferred its contents to Johnson's office last week upon his request. That came as Paul's committee voted along party lines to hold Fauci in contempt of Congress earlier this month for pleading the Fifth Amendment while appearing before the panel.

The initial release Monday included a very small sample size -- fewer than a dozen texts -- and marked the latest public scrutiny of Fauci's tenure as the nation's top infectious disease expert during the Covid pandemic. The texts show Fauci having real-time discussions in late January 2021 about the pros and cons of the Covid vaccine for pregnant women with then-Surgeon General Dr. Vivek Murthy and Dr. Rochelle Walensky, who at the time led the Centers for Disease Control and Prevention.

In response to a query from Murthy, Fauci wrote that there was "no data or theoretical reason" to prefer vaccinating early over later in pregnancy. Fauci said that since many people experienced fever and an overactive immune response, known as cytokine storm, after their second Covid vaccine dose, it "theoretically could be associated with miscarriage in the 1st trimester."

The following day, Murthy asked Fauci and Walensky about a World Health Organization announcement advising pregnant women against Moderna's Covid vaccine because of limited data. Fauci said the potential risks and benefits should always be weighed when data on vaccination during pregnancy are limited. He later said Covid could cause serious illness during pregnancy and that no safety issues had emerged among more than 10,000 pregnant women who had received the vaccine.

He also pointed to guidance from U.S. health authorities, including the CDC's Advisory Committee on Immunization Practices (ACIP) and the American College of Obstetricians and Gynecologists, which left the decision to women and their healthcare providers.

Both Murthy and Walensky agreed with Fauci's observations, which were consistent with the federal recommendations at the time.

The CDC didn't explicitly recommend that pregnant women get the Covid vaccine until April 2021, citing new safety data. ACOG and the Society for Maternal-Fetal Medicine (SMFM), the two leading organizations representing specialists in obstetric care, made a similar recommendation in July of that year. Under Health and Human Services Secretary Robert F. Kennedy Jr., the Trump administration has broken from those groups by nixing federal guidance that pregnant women get Covid-19 vaccines as a matter of routine.

ACOG and SMFM have maintained that the Covid vaccine is safe and effective during pregnancy, noting that Covid itself poses greater risks to pregnant women and their infants.

Fauci and Walensky declined to comment. Murthy's office didn't immediately return a request for comment.

Johnson's office said it would take time to review the phone records in their entirety, but signaled he and Paul planned to make more of Fauci's communications public. His office added that only three contacts were listed in the phone, and that it was too early to determine whether any data had been deleted. Following the release of Fauci's texts, Johnson told Fox News that his committee has invited the 85-year-old doctor to a "private, transcribed interview" and that he will subpoena Fauci if he refuses.

Paul's office has also released copies of Fauci's Covid-era diaries that it received from HHS.

Fauci played a central role in the federal government's pandemic response in President Trump's first term and under former President Joe Biden. Paul, a longtime Fauci critic, has accused the doctor of supporting dangerous research that some scientists believe may have caused the first coronavirus cases, conspiring to discredit that theory, evading federal transparency laws and ignoring evidence that conflicted with his preferred public-health measures. Fauci and his legal team have said the allegations are false.