Covid Immunity Through Infection or Vaccination: Are They Equal?

Covid Immunity Through Infection or Vaccination: Are They Equal?

Dr. Aaron Kheriaty, a University of California-Irvine psychiatry professor, felt he didn’t need to be vaccinated against covid because he’d fallen ill with the disease in July 2020.

So, in August, he sued to stop the university system’s vaccination mandate, saying “natural” immunity had given him and millions of others better protection than any vaccine could.

A judge on Sept. 28 dismissed Kheriaty’s request for an injunction against the university over its mandate, which took effect Sept. 3. While Kheriaty intends to pursue the case further, legal experts doubt that his and similar lawsuits filed around the country will ultimately succeed.Originally published in Kaiser Health News.

 

That said, evidence is growing that contracting SARS-CoV-2, the virus that causes covid-19, is generally as effective as vaccination at stimulating your immune system to prevent the disease. Yet federal officials have been reluctant to recognize any equivalency, citing the wide variation in covid patients’ immune response to infection.

Like many disputes during the covid pandemic, the uncertain value of a prior infection has prompted legal challenges, marketing offers and political grandstanding, even as scientists quietly work in the background to sort out the facts.

For decades, doctors have used blood tests to determine whether people are protected against infectious diseases. Pregnant mothers are tested for antibodies to rubella to help ensure their fetuses won’t be infected with the rubella virus, which causes devastating birth defects. Hospital workers are screened for measles and chickenpox antibodies to prevent the spread of those diseases. But immunity to covid seems trickier to discern than those diseases.

The Food and Drug Administration has authorized the use of covid antibody tests, which can cost about $70, to detect a past infection. Some tests can distinguish whether the antibodies came from an infection or a vaccine. But neither the FDA nor the Centers for Disease Control and Prevention recommend using the tests to assess whether you’re, in fact, immune to covid. For that, the tests are essentially useless because there’s no agreement on the amount or types of antibodies that would signal protection from the disease.

“We don’t yet have full understanding of what the presence of antibodies tells us about immunity,” said Kelly Wroblewski, director of infectious diseases at the Association of Public Health Laboratories.

By the same token, experts disagree on how much protection an infection delivers.

In the absence of certainty and as vaccination mandates are levied across the country, lawsuits seek to press the issue. Individuals who claim that vaccination mandates violate their civil liberties argue that infection-acquired immunity protects them. In Los Angeles, six police officers have sued the city, claiming they have natural immunity. In August, law professor Todd Zywicki alleged that George Mason University’s vaccine mandate violated his constitutional rights given he has natural immunity. He cited a number of antibody tests and an immunologist’s medical opinion that it was “medically unnecessary” for him to be vaccinated. Zywicki dropped the lawsuit after the university granted him a medical exemption, which it claims was unrelated to the suit.

Republican legislators have joined the crusade. The GOP Doctors Caucus, which consists of Republican physicians in Congress, has urged people leery of vaccination to instead seek an antibody test, contradicting CDC and FDA recommendations. In Kentucky, the state Senate passed a resolution granting equal immunity status to those who show proof of vaccination or a positive antibody test.

Hospitals were among the first institutions to impose vaccine mandates on their front-line workers because of the danger of them spreading the disease to vulnerable patients. Few have offered exemptions from vaccination to those previously infected. But there are exceptions.

Two Pennsylvania hospital systems allow clinical staff members to defer vaccination for a year after testing positive for covid. Another, in Michigan, allows employees to opt out of vaccination if they present evidence of previous infection and a positive antibody test in the previous three months. In these cases, the systems indicated they were keen to avoid staffing shortages that could result from the departure of vaccine-shunning nurses.

For Kheriaty, the question is simple. “The research on natural immunity is quite definitive now,” he told KHN. “It’s better than immunity conferred by vaccines.” But such categorical statements are clearly not shared by most in the scientific community.

Dr. Arthur Reingold, an epidemiologist at UC-Berkeley, and Shane Crotty, a virologist at the respected La Jolla Institute for Immunology in San Diego, gave expert witness testimony in Kheriaty’s lawsuit, saying the extent of immunity from reinfection, especially against newer variants of covid, is unknown. They noted that vaccination gives a huge immunity boost to people who’ve been ill previously.

Yet not all of those pushing for recognition of past infection are vaccine critics or torchbearers of the anti-vaccine movement.

Dr. Jeffrey Klausner, clinical professor of population and public health sciences at the University of Southern California, co-authored an analysis published last week that showed infection generally protects for 10 months or more. “From the public health perspective, denying jobs and access and travel to people who have recovered from infection doesn’t make sense,” he said.

In his testimony against Kheriaty’s case for “natural” immunity to covid, Crotty cited studies of the massive covid outbreak that swept through Manaus, Brazil, early this year that involved the gamma variant of the virus. One of the studies estimated, based on tests of blood donations, that three-quarters of the city’s population had already been infected before gamma’s arrival. That suggested that previous infection might not protect against new variants. But Klausner and others suspect the rate of prior infection presented in the study was a gross overestimate.

A large August study from Israel, which showed better protection from infection than from vaccination, may help turn the tide toward acceptance of prior infection, Klausner said. “Everyone is just waiting for Fauci to say, ‘Prior infection provides protection,’” he said.

When Dr. Anthony Fauci, the top federal expert on infectious diseases, was asked during a CNN interview last month whether infected people were as well protected as those who’ve been vaccinated, he hedged. “There could be an argument” that they are, he said. Fauci did not immediately respond to a KHN request for further comment.

CDC spokesperson Kristen Nordlund said in an email that “current evidence” shows wide variation in antibody responses after covid infection. “We hope to have some additional information on the protectiveness of vaccine immunity compared to natural immunity in the coming weeks.”

A “monumental effort” is underway to determine what level of antibodies is protective, said Dr. Robert Seder, chief of the cellular immunology section at the National Institute of Allergy and Infectious Diseases. Recent studies have taken a stab at a number.

Antibody tests will never provide a yes-or-no answer on covid protection, said Dr. George Siber, a vaccine industry consultant and co-author of one of the papers. “But there are people who are not going to be immunized. Trying to predict who is at low risk is a worthy undertaking.”

When Will Kids Receive Covid Vaccinations?

When Will Kids Receive Covid Vaccinations?

If clinical trials for COVID-19 vaccines aren’t expanded soon to include children, it’s unlikely that even kids in their teens will be vaccinated in time for the next school year.

The hurdle is that COVID vaccine makers are only in the early stages of testing their products on children. The Pfizer vaccine authorized for use by the Food and Drug Administration on Friday was greenlighted only for people ages 16 and up. Moderna just started trials for 12- to 17-year-olds for its vaccine, likely to be authorized later this month.

It will take months to approve use of the vaccines for middle- and high school-aged kids, and months more to test them in younger children. But some pediatricians say that concerns about the safety of the front-runner vaccines make the wait worthwhile.

Although most pediatricians believe the eventual vaccination of children will be crucial to subduing the COVID virus, they’re split on how fast to move toward that, says Dr. James Campbell , professor of pediatrics at the University of Maryland School of Medicine’s Center for Vaccine Development and Global Health. Campbell and colleagues say it’s a matter of urgency to get the vaccines tested in kids, while others want to hold off on those trials until millions of adults have been safely vaccinated.

Much of the debate centers on two issues: the degree of harm COVID-19 causes children, and the extent to which children are spreading the virus to their friends, teachers, parents and grandparents.

COVID-19’s impact on children represents a tiny fraction of the suffering and death experienced by vulnerable adults. Yet it would qualify as a pretty serious childhood disease, having caused 154 deaths and more than 7,500 hospitalizations as of Dec. 3 among people 19 and younger in the United States. Those numbers rank it as worse than a typical year of influenza, and worse than diseases like mumps or hepatitis B in children before the vaccination era.

Studies thus far show that 1%-2% of children infected with the virus end up requiring intensive care, Dr. Stanley Plotkin, professor emeritus of pediatrics at the University of Pennsylvania, told a federal panel. That’s in line with the percentage who become gravely ill as result of infections like Haemophilus influenza type B, or Hib, for which doctors have vaccinated children since the 1980s, he pointed out.

Campbell, who with colleagues has developed a plan for how to run pediatric COVID vaccine trials, points out that “in a universe where COVID mainly affected children the way it’s affecting them now, and we had potential vaccines, people would be clamoring for them.”

The evidence that teens can transmit the disease is pretty clear, and transmission has been documented in children as young as 8. Fear of spread by children has been enough to close schools, and led the American Academy of Pediatrics to demand that children be quickly included in vaccine testing.

“The longer we take to start kids in trials, the longer it will take them to get vaccinated and to break the chains of transmission,” said Dr. Yvonne Maldonado, a professor of pediatrics at Stanford University who chairs the AAP’s infectious disease committee. “If you want kids to go back to school and not have the teachers union terrified, you have to make sure they aren’t a risk.”

Other pediatricians worry that early pediatric trials could backfire. Dr. Cody Meissner, chief of pediatric infectious diseases at Tufts Medical Center and a member of the FDA’s advisory committee on vaccines, is worried that whatever causes Multisystem Inflammatory Syndrome in Children, a rare but frightening COVID-related disorder, might also be triggered, however rarely, by vaccination.

Meissner abstained from the committee’s vote Thursday that supported, by a 17-4 vote, an emergency authorization of the Pfizer vaccine for people 16 and older.

“I have trouble justifying it for children so unlikely to get the disease,” he said during debate on the measure.

But panel member Dr. Ofer Levy, director of the Precision Vaccines Program at Boston Children’s Hospital, said the 16-and-up authorization would speed the vaccine’s testing in and approval for younger children. That is vital for the world’s protection from COVID-19, he said, since in the United States and most places “most vaccines are delivered early in life.”

While vaccines given to tens of thousands of people so far appear to be safe, the lack of understanding of the inflammatory syndrome means that children in any trials should be followed closely, said Dr. Emily Erbelding, director of the Division of Microbiology and Infectious Diseases at the National Institute of Allergy and Infectious Diseases.

Under a 2003 law, vaccine companies are required eventually to test all their products on children. By late last month, Pfizer had vaccinated approximately 100 children 12-15 years of age, said spokesperson Jerica Pitts.

Moderna has started enrolling 3,000 children 12 and over in another clinical trial, and other companies have similar plans. Assuming the trials show the vaccines are safe and provide a good immune response, future tests could include progressively younger children, moving to, say, 6- to 12-year-olds next, then 2- to 6-year-olds. Eventually, trials could include younger toddlers and infants.

Similar stepdown approaches were taken to test vaccines against human papillomavirus (HPV), influenza and other diseases in the past, Erbelding noted. Such trials are easiest to conduct when researchers know that a measurable immune response, like antibody levels in the blood, translates to effective protection against disease. Armed with such knowledge, they can see whether children were protected without them having to be exposed to the virus. Federal scientists hope to get that data from the Moderna and Pfizer adult vaccine trials, she said.

Vaccine trials geared to tweens or younger children may involve testing half-doses, which, if protective, would require less vaccine and might cause fewer incidents of sore arms and fevers that afflicted many who’ve received the Pfizer and Moderna vaccines, Campbell said.

But unless additional studies begin quickly, the window for having an FDA-authorized vaccine available before the next school year “will be closed even for our oldest children,” said Dr. Evan Anderson, a pediatrics professor at Emory University. “Our younger children are almost certainly going into next school year without a vaccine option available for them.”

In the meantime, teachers are likely to be high on the priority list for vaccination. Protecting school staff could allow more schools to reopen even if most children can’t be vaccinated, Erbelding said.

Eventually, if the SARS-CoV-2 virus remains in circulation, governments may want to mandate childhood vaccination against the virus to protect them as they grow up and protect society as a whole, Plotkin said.

In the 1960s, Plotkin invented the rubella vaccine that has been given to hundreds of millions of children since. Like COVID-19, rubella, or German measles, is not usually a serious illness for children. But congenital rubella syndrome afflicted babies in the womb with blindness, deafness, developmental delays and autism. Immunizing toddlers, which, in turn, protects their pregnant mothers, has indirectly prevented hundreds of thousands of such cases.

“We don’t want to use children to protect everyone in the community,” said Campbell. “But when you can protect both children and their community, that’s important.”

And while a coronavirus infection may not be bad for most children, missed school, absent friends and distanced families have caused them immense suffering, he said.

“It’s a huge burden on a child to have their entire world flipped around,” Campbell said. “If vaccinating could help to flip it back, we should begin testing to see if that’s possible.”

This story was produced by KHN, which publishes California Healthline, an editorially independent service of the California Health Care Foundation.

Published courtesy of KHN (Kaiser Health News), a nonprofit news service covering health issues. It is an editorially independent program of KFF (Kaiser Family Foundation), which is not affiliated with Kaiser Permanente.