What is the best description of past vaccine development efforts for coronaviruses?

The assertion that a vaccine against MERS provided long-lasting immunity reflects key findings from vaccine development efforts. While clinical trials for vaccines targeting the MERS coronavirus have shown promise and indicated that they can elicit immune responses, many of these vaccines are still under evaluation for their durability.

MERS-CoV has been a focus of vaccine research since it was first identified due to its serious health implications. Most notably, some candidate vaccines demonstrated the ability to induce robust antibody responses in non-human primates, offering potential for longer-lasting immunity. Research into various vaccine platforms for MERS has included approaches such as DNA vaccines, viral vectors, and protein subunit vaccines, which support the notion that effective vaccination strategies can be developed for this virus.

In contrast, the development of vaccines for SARS showed more challenges, as the initial candidates did not provide long-term immunity and raised concerns about enhanced disease upon re-exposure. This aspect highlights the complexity of vaccine responses against coronaviruses and why the assertion regarding MERS specifically stands out within the context of past vaccine efforts.