Vaccines work. All of them

Published June 8, 2021, 12:10 AM

by Dr. Edsel Salvana

How did Sinovac become the first vaccine to be available in the Philippines?

Dr. Edsel Maurice T. Salvana

On June 1, 2021 the World Health Organization (WHO) approved the inclusion of Sinovac (Coronavac) in its COVID-19 vaccine Emergency Use Listing (EUL). The EUL is a list of vaccines reviewed by the WHO and found to meet its standards for safety and efficacy. After several months of review, the WHO stated that Sinovac passed stringent criteria for EUL listing, joining the arsenal of prequalified vaccines that it could procure in the fight against COVID-19.  

For many countries that have been using Sinovac, this is an affirmation that the choice to roll out this new vaccine prior to obtaining an imprimatur from the WHO was the right decision. A WHO EUL is not required for the approval of a vaccine in a country. That job falls on the country’s Food and Drug Authority or an equivalent regulatory body. All current WHO EUL vaccines previously received either emergency use authority (EUA) or limited approval in their home countries prior to receiving WHO EUL designation. The six vaccines with EULs as of this writing are Pfizer, Astra, Moderna, J&J, Sinopharm, and Sinovac. Other vaccines that are currently being used by different countries have submitted or are in the process of submitting documents for WHO EUL. As long as a vaccine meets the standards and undergoes careful review by the WHO’s Strategic Advisory Group of Experts on Immunization (SAGE), an EUL designation is expected to be given.

With the recent surge of cases in India, the vaccines India had previously committed to deliver to the global community have been diverted for its own use. European countries and the US prioritized their own populations and held back supplies despite having enough to vaccinate their populations several times over. Chinese vaccines have filled the void, despite concerns about transparency and the lack of peer-reviewed data. COVID-19 Vaccines Global Access (COVAX) is a worldwide initiative aimed at equitable access to vaccines globally. An EUL is a prerequisite for inclusion in the COVAX vaccine facility.

In the Philippines, the early decision to use Sinovac was very contentious. There were accusations of overpricing, blocking entry of other vaccines, as well as preferential treatment for a vaccine from a perceived administration ally. This occurred even before any supply agreements for the vaccine had been finalized. No other vaccines makers were willing to commit to delivering earlier than March 2021, and it was announced that the Chinese government would donate the first one million doses.

Adding a layer of confusion, the initial FDA EUA for Sinovac was accompanied by a pronouncement that it was not recommended for healthcare workers, due to the relatively low vaccine efficacy against mild disease in some of the clinical trials. The clinical trial in question was a study in Brazil that exclusively enrolled highly exposed healthcare workers. The vaccine efficacy against symptomatic disease was 50.4 percent, but efficacy was 100 percent against severe disease and death. The FDA also did not recommend Sinovac for those above 60 years old and for those with chronic diseases. The situation was exacerbated by a lack of published, peer-reviewed data from the manufacturer, although this is not a requirement for receiving an EUA.

Since the COVAX facility had initially committed to delivering Pfizer vaccines as early as February, this was not seen as a major hurdle. The plan was to give Pfizer to the A1 (healthcare workers), A2 (seniors), and A3 (chronic illnesses) priority groups and go ahead and do a simultaneous rollout of Sinovac for A4 (essential workers). Unfortunately, the Pfizer vaccines were delayed and the National Immunization Technical Advisory Group (NITAG) was asked by the government to decide to which group the upcoming Sinovac shipment was going to be given. Faced with the prospect of no clear timelines for when another vaccine would arrive, the NITAG elected to give healthcare workers a choice between accepting Sinovac or waiting for the next available vaccine brand without losing their place in line. The manufacturer also allowed the NITAG, the Technical Advisory Group (TAG), and the Health Technology Assessment Council (HTAC) to review the unpublished data under a non-disclosure agreement to properly make its recommendation. The FDA agreed that this recommendation did not contradict its determination for healthcare workers as there was no other vaccine available and that early protection was preferable to no protection.

Under these circumstances, accusations of a setup and a bias for Chinese vaccines were hurled against the government and the NITAG. This was despite many independent medical and scientific experts weighing in on the safety and efficacy of Sinovac, particularly for severe disease. The NITAG explained that the best vaccine was the one that was available, especially for those at highest risk for exposure and death.

In several twists worthy of a telenovela, there was a highly publicized leak of an unsigned HTAC document purportedly showing dubious efficacy of the vaccine. A group of healthcare workers at the Philippine General Hospital staged a rally that they were not going be made to take an “inferior” vaccine. Many healthcare workers in the hospitals that were targeted for initial rollout expressed reluctance to take the vaccine, and the NITAG attempted to address this with a series of townhall meetings. During the PGH townhall meeting to convince skeptical healthcare workers that this was in their best interest, word came that the Astra vaccine was arriving a few days after the Sinovac shipment. In another plot twist, shortly after Sinovac was delivered, the WHO announced that the Astra shipment would be delayed. This served to further heighten suspicions of bias, despite the WHO’s explanation that the government had nothing to do with the delay.

Nevertheless, the initial rollout pushed through. Reluctant PGH healthcare workers who witnessed the inoculation of PGH director Geraldo “Gap” Legaspi, myself, FDA director general, Rolando Domingo, and others eventually lined up to get the vaccine after they saw that we survived the injection. PGH ran out of its first day allocation of Sinovac despite fewer than one hundred people initially signing up. When the Astra shipment finally arrived, the vaccination program was well under way. To address the lack of vaccines for elderly individuals and in response to a clamor for Sinovac from the seniors themselves, the FDA eventually agreed to allow the use of Sinovac for this population after further review.

This brings us to the current WHO EUL, which serves as validation that Sinovac is safe and effective. Sinovac has been the most used vaccine locally and has had the most reliable supply. Succeeding real-world data now shows that Sinovac is up to 94 percent effective for symptomatic disease and continues to almost completely protect against severe disease and death. Transmission blocking studies in Brazil using Sinovac, the first of its kind for any COVID-19 vaccine, showed mass vaccination in the town of Serrana resulted in a decrease of cases by 80 percent and deaths by 95 percent in the early phases of follow-up. It is clear that Sinovac, along with all the other vaccines being used in our country, works very well and is already saving lives.

Reminiscent of the Dengvaxia controversy, partisan politics has once again reared its ugly head. Politicizing vaccination erodes vaccine confidence, and results in serious public health consequences.  When vaccines are judged based on their country of origin or considerations other than objective scientific merit, people die needlessly. Preserving confidence in vaccines saves lives.