Four years out from the onset of the COVID-19 epidemic, a new study explores the extent to which COVID-19 and influenza vaccines are being distributed and employed simultaneously, particularly among high-risk populations.
COVID-19 and influenza can be particularly dangerous for older adults, causing high rates of hospitalization and mortality. In the U.S., hospitalized veterans aged 65 and older face a 30-day mortality risk of 6.4% for COVID-19 and 3.7% for influenza—significantly higher than younger populations. Recent research highlights the efficacy of vaccines in preventing these diseases or lessening their severity, with vaccination efforts averting thousands of flu-related and millions of COVID-19-related hospitalizations nationwide.
In this context, a new study conducted by Daniel Harris, senior research scientist, and Vincent Mor, professor of health services policy and practice and the Florence Pierce Grant University Professor at Brown University, explores the adoption and variability of simultaneous COVID-19 and flu vaccinations. Supported by an IMPACT grant from the National Institute on Aging, their research expands on previous findings regarding the benefits of co-administered vaccines, examining whether these vaccinations are being adopted broadly and if any specific groups are being overlooked.
The paper, “COVID-19 and influenza vaccine coadministration among older U.S. adults,” analyzed a national sample of U.S. Medicare beneficiaries to assess the timing and location of vaccine administration and to explore the demographic, social and health factors that may influence the likelihood of an individual receiving concurrent vaccines.
“We had the very unique opportunity to study COVID-19 and influenza vaccine uptake in millions of Medicare beneficiaries over time,” Harris said. “I was personally surprised by the lower rate of vaccine co-administration in the U.S. and quite concerned by clear disparities in vaccine access among Black, Native American and Hispanic Medicare beneficiaries.”
Despite initial reluctance in certain regions due to concerns about safety and efficacy, the majority of public health authorities now endorse the co-administration of COVID-19 and flu vaccines, supported by positive results from clinical trials.
“There are several logistical, clinical, and public health benefits to the co-administration of vaccines,” the authors write. “Vaccine co-administration results in fewer health care visits and is more cost effective. Pairing vaccines also reduces the time to receive protection against co-circulating viruses, as opposed to waiting for multiple visits (where attrition may also occur).” Receiving COVID-19 and flu shots together, they go on to say, “is a natural public health strategy to improve convenience and uptake.”
By the numbers
The study acknowledges an encouraging increase in the number of older adults getting COVID-19 and flu vaccines simultaneously. However, it also reveals variation in vaccination rates influenced by geography, health status, and race and ethnicity.
The co-administration of COVID-19 and flu vaccines increased over two flu seasons—from 11.1% in 2021 to 36.5% in 2022—but varied across different regions. People in rural areas and those with Alzheimer’s and related dementias were more likely to get concurrent vaccinations. In contrast, patients with cancer or immune disorders were less likely to receive both vaccinations during the same visit; they were, however, more likely to receive a flu vaccine than other patient groups but received their shots on different days.
The study also highlights the differences in flu vaccination rates among people of different races, ethnicities and living areas, confirming what previous research has also shown. For instance, during one study period, only about 10% of vaccinated white people hadn’t gotten the flu shot, compared to around 21% of Black people, 16% of Hispanic people, and 17% of Native Americans. The researchers note that while Native Americans were less likely to get a flu shot compared to white people, they were more likely to get it at the same time as another vaccine, possibly because they often live in more rural areas or because of tailored public health messages encouraging simultaneous vaccinations.
When looking only at people who did get a flu shot during a second study period, Black and Hispanic people were slightly more likely to have both vaccines administered at the same time than white people. This suggests that the variations in getting concurrent vaccinations are more about access, rather than differences in willingness to receive multiple vaccines at once.
“Vaccines played a major role in blunting and subsequently ending the global, COVID-19 public health emergency,” Harris said. “But COVID-19, and other vaccine-preventable illnesses like flu, aren’t going away anytime soon. Our study documents gaps and opportunities to expand vaccination coverage in the US.”
The researchers emphasize the importance of promoting the simultaneous administration of these vaccines, particularly during flu season, as a strategy to enhance vaccination rates and ensure broader protection against these diseases. Building on their prior work, which confirms the safety of COVID-19 vaccines in older adults, they advocate for future research to investigate the research to investigate the reasons behind variations in uptake and to develop strategies to guarantee equitable access to these vaccines.
Source: Brown School of Public Health
