The Moderna COVID-19 vaccine is safe for most people including those with a wide range of underlying medical conditions, according to the World Health Organization’s Strategic Advisory Group of Experts (SAGE) on immunizations.

However, the vaccine is not recommended for pregnant women or children as it has not been tested on these groups, according to interim recommendations published today by WHO.  The issue of the vaccine in pregnancy is emerging as a bigger issue in light of recent evidence, including from the US Centers for Disease Control, that pregnant women are at higher risk of serious COVID-19, and as new variants of the SARS-CoV2 virus infect more young people, including those of childbearing age.

The WHO approval may also pave the way for Moderna to contribute vaccines to the global COVAX facility, following a final WHO “Emergency Use Listing” approval for the vaccine.

Last Friday, Pfizer announced it was contributing 40 million doses of its vaccine to the WHO co-sponsored COVAX, weeks after WHO approved the vaccine.

People who have severe allergic reactions to any of the vaccine’s components should not receive it, and it should also not be used in countries that do not have the capacity to treat anaphylactic shock, according to SAGE. It also advises caution about administering the vaccine to frail, elderly people near the end of their lives.

The vaccine needs to be administered in two doses 28 days apart, although “the interval between the doses may be extended to 42 days”, SAGE said. All those vaccinated should be observed for “at least 15 minutes after vaccination”, and anyone experiencing an immediate severe allergic reaction should not receive the additional dose.

No Word On Emergency Authorization From WHO

The WHO has not yet issued an Emergency Use Listing (EUL) for the Moderna vaccine, but it has undergone review by the European Medical Agency (EMA), which has authorized its use in the European Union. It has also been approved in the United States, Canada, the United Kingdom and Swissmedic.

Regardless, the WHO advice is significant as many member states – especially low- and middle-income countries (LMICs) – also rely upon WHO for vaccine recommendations as a global reference point.

Dr Kate O’Brien, WHO’s Director of Vaccines, told a media briefing today that the global body was still in discussions with Moderna about the information it needed to issue an EUL, and so did not comment about if or when this would be issued.

O’Brien did add, however, that SAGE’s advice was important as some member states had already made arrangements to procure the vaccine from Moderna.

Moderna and Pfizer/BioNTech are both mRNA-based vaccines, but the Moderna vaccine does not need to be stored at the extremely cold temperatures required by the BioNTech-Pfizer vaccine, which makes it more suitable for LMICs.

In trials, the Moderna vaccine showed an efficacy of approximately 92% in protecting against COVID-19, starting 14 days after the first dose.

Moderna claimed yesterday that its candidate appears to retain its efficacy against the B.1.1.7 and South Africa-identified (B.1.351) variants. In the study, which is yet to be peer-reviewed, researchers looked at blood samples from eight participants who had previously received the recommended two doses during Phase 1 trials.

In the case of the B.1.1.7 variant, they reported the mutated virus posed no significant impact on titers: a means for measuring the amount of antibodies in a blood sample. Tests on B.1.351 showed a “six-fold reduction in neutralizing titers” although “neutralizing titer levels with B.1.351 remain above levels that are expected to be protective”, according to the company media release.

Meanwhile, Moderna also announced that it will “test an additional booster dose of its COVID-19 Vaccine (mRNA-1273)” to see whether it can further increase neutralizing antibodies against emerging strains “beyond the existing primary vaccination series”.

Despite this, O’Brien said that clinical evidence was needed to support this report, and that the blood sera of people who have antibodies against COVID-19 was currently being tested against these variants.

She welcomed how prepared vaccine manufacturers were to “potentially make modifications to the vaccines that they are continuing to develop”.

“The preponderance of evidence at hand, albeit small, is that the vaccines in hand are extremely valuable as part of the toolbox for fighting the pandemic and really crushing this virus, but we will continue to respond to as new scientific evidence comes in,” concluded O’Brien.

Image Credits: Moderna.