People with systemic lupus erythematosus (SLE), who received a booster dose of SARS-CoV-2 vaccine after full vaccination, are roughly half as likely to have a subsequent breakthrough COVID-19 infection, according to a new online study (“COVID-19 Breakthrough Infections, Morbidity, and Seroreactivity in SLE Patients Following Additional COVID-19 Vaccination Series and Additional Dose in Patients with SLE in New York City”) in The Lancet Rheumatology.

The finding, researchers say, should offer reassurance to the more than 200,000 Americans who have SLE, a condition in which the body’s immune system mistakenly attacks its own healthy tissues, especially joints and skin. Immune-suppressing drugs, such as steroids, needed to control symptoms of the disease, place them at increased risk of infections, including SARS-CoV-2.

Led by researchers at NYU Grossman School of Medicine, the new study tracked the health of 163 fully vaccinated men and women being treated for SLE at its affiliated hospitals in New York City. The researchers’ goal was to see who became infected with the virus over at least six months, given that more than half were taking at least one immune-suppressing medication for their SLE.

All had received some combination of the vaccines manufactured by Pfizer, Moderna, or Johnson & Johnson prior to June 2021, but only 125 had received a third or booster dose of vaccine. The study showed that at the end of the monitoring period, 44 vaccinated SLE patients had had breakthrough infections, with two needing hospitalization (but both surviving their infection).

Among those with breakthrough infections, 28 of 125, or 22%, had received a booster, while 16 of 38, or 42%, had not. Notably, according to investigators, the majority of breakthrough infections (42 of 44) occurred after Dec. 2, 2021, when the city detected its first case of the highly contagious omicron variant.

Another key study finding was among 57 of the study participants who agreed to have their blood antibody levels checked, once after full vaccination and again after receiving their booster.

Immunosuppressed displayed antibody level rise after booster shot

Researchers found that even those on immunosuppression who had not responded to the initial round of vaccination had an immediate rise in antibody levels after the administration of a booster shot. Previous research had shown that these antibody levels were lower among many initially vaccinated patients with rheumatic diseases, including SLE, who were taking immune-suppressing drugs, sparking fears of waning immunity to COVID-19 over time.

However, study results showed those with higher levels of antibodies, needed to block the SARS-Cov-2 spike protein and prevent the virus from infecting human cells, were no more protected from breakthrough infection than those with lower spike-protein antibody levels.

Still, researchers say their previous work showed elevated antibody levels in fully vaccinated lupus patients strengthened key measures of long-term immunity, which may help explain the lack of severe disease in those with breakthrough infections.

“Our study results offer people living with systemic lupus erythematosus clinical confirmation that vaccines are highly effective at guarding against severe COVID-19, despite their increased risk of catching the disease,” said study co-lead investigator and rheumatologist Amit Saxena, MD, an assistant professor in the department of medicine at NYU Langone Health. “COVID-19 vaccine boosters, or third shots, offered an added, doubled layer of protection from breakthrough infection. Even in cases of SARS-CoV-2 infection, cases were overwhelmingly mild among SLE patients who were fully vaccinated.”

“Our research also shows that most people with systemic lupus erythematosus who are fully vaccinated and boosted mounted good responses despite being on immune suppression,” added study co-senior investigator and rheumatologist Peter Izmirly, MD, an associate professor in the department of medicine at NYU Langone Health.

However, researchers caution that further monitoring of patients is needed to determine if there is any antibody cutoff level below which SLE patients become more vulnerable to SARS-CoV-2 infection.

See also in GEN, “Vaccine Study Explores COVID-19 and Autoimmune Disease” and “Resource Links Gene Variants with Immune System Regulation and Immune-Mediated Disease.”