Moderna vaccine may cause fewer breakthrough infections than Pfizer

key takeaways

  • A recent study showed that recipients of Moderna’s COVID-19 vaccine had a lower risk of breakthrough infection and hospitalization than those who received Pfizer’s vaccine.
  • More research is needed to understand the reasons behind this risk difference.
  • The overall risk of breakthrough infection is low.

The COVID-19 vaccine is very effective at preventing serious illness and death, but it does not completely eliminate the risk of infection. This means that vaccine breakthrough infections — which occur when a fully vaccinated person becomes infected — are to be expected.

However, according to a recent publication in JAMA, the risk of breakthrough infection varies depending on the vaccine you have received. Moderna COVID-19 vaccine recipients had a lower risk of breakthrough infection and hospitalization than Pfizer vaccine recipients.

Researchers analyzed electronic health records of more than 637,000 fully vaccinated patients and studied breakthrough infections that occurred between July 2021 and November 2021, when Delta was the predominant variant circulating in the U.S.

By November 2021, the monthly breakthrough infection rate for Pfizer vaccinated people reached 2.8 cases per 1,000 people, compared with 1.6 cases for Moderna.

More research is needed to understand the reasons behind this risk and how these results stack up against Omicron variants.

Can mRNA boosters prevent Omicron?

Why are the risks of breakthrough infections different?

The study did not delve into why there were differences in risk between the two vaccines.

“It is difficult to make direct comparisons from observational data because there may be many confounding factors that may not have been measured in the analysis,” said Shobha Swaminathan, MD, associate professor of medicine at Rutgers University and medical director of the university’s infectious disease practice hospital, told VigorTip. . “Vaccines are also slightly different.”

Vaccines are not all the same, so it makes sense that they also have different risks of breakthrough infections. For now, experts can only speculate as to why people who get the Pfizer vaccine appear to be at higher risk.

For example, the Moderna vaccine contains 100 micrograms of mRNA, and the Pfizer vaccine contains 30 micrograms, which might work. The former has a dosing interval of 28 days, while the latter requires only a 21-day interval. Published in 2021 cell Antibody levels were found to be much higher when the dosing interval of the Pfizer vaccine was extended to 6 to 14 weeks.

Breakthrough COVID: If you were vaccinated, could you test positive?

Some experts have speculated whether Pfizer’s patients were vaccinated before Moderna’s patients. Pfizer’s vaccine was authorized weeks before Moderna. Vaccine protection wanes over time, so people who get vaccinated earlier may be more vulnerable to breakthrough infections. But in this study, that may not be the case.

“When we compared infections and outcomes between these two vaccine recipients, we had taken into account patient characteristics and different timing of vaccination,” said study author Dr. Xu Rong, director of the Center for Artificial Intelligence Drug Discovery. Case Western Reserve University told Very Well.

Although the risk of breakthrough infection is generally low, infection rates can also vary depending on an individual’s underlying health conditions. “Our data show that the breakthrough infection rate may be quite high in patients with blood cancer, colorectal cancer or lung cancer,” Xu added.

what does this mean to you

The risk of breakthrough infection and hospitalization may be slightly higher for those receiving the Pfizer vaccine, but the vaccine is still highly protective against severe illness and death. Overall, the risk of contracting COVID-19 in unvaccinated people remains much higher than in vaccinated people.

Should you be worried if you have Pfizer?

Breakthrough infections are usually uncommon no matter which mRNA vaccine you get.

“Although the differences between the two vaccines were statistically significant, they were not significantly different,” Xu said. “The overall risk of breakthrough infection and hospitalization was low in both vaccine recipients.”

If you are fully vaccinated and have COVID-19, you are still less likely to get seriously ill than someone who has not been vaccinated.

“I think, despite the differences, both vaccines are very effective in reducing hospitalizations, and both vaccines are equally effective in preventing deaths from COVID-19,” Swaminathan said.

According to the data, there was no significant difference in mortality between the two vaccine recipients. While the risk of a breakthrough infection will never be zero, it’s important to remember that vaccines are still very effective at what they’re supposed to do: protect against the worst consequences of COVID-19.

Does Omicron increase the risk of reinfection with COVID-19?

How about the Omicron variant?

The Omicron variant may have a higher risk of breakthrough infection, but we need more data to know for sure.

“The Omicron variant is completely different from the original virus and therefore able to cause more infections,” Swaminathan said. “However, it seems clear that while we’re seeing breakthrough infections, most infections are still mild, and hospitalizations, ICU admissions, and mortality rates among those who have been vaccinated and boosted remain extremely low.”

The researchers looked at cases of breakthrough infections during the delta period, but Omicron is now the dominant variant. We have not seen whether there are also significant differences in breakthrough infection and hospitalization risk between the two mRNA vaccines.

Can a vaccinated person be a long-distance transporter?

“We are currently working on comparing the effects of these vaccines on Omicron-related infection and outcomes,” Xu said.

Overall, the risk of a breakthrough infection is low, but to be cautious, experts recommend that you continue to take precautions.

“It still goes back to the basics of wearing a mask in public when indoors, maintaining frequent hand hygiene and making sure you and those around you are vaccinated and given booster doses,” Swaminathan said.

The information in this article is current as of the date listed, which means that you may have updated information as you read this article. For the latest updates on COVID-19, visit our Coronavirus news page.