On Nov 9th, the drugmaker Pfizer announced that Phase 3 of their coronavirus vaccine trial yielded positive findings and was effective in preventing Covid-19.

In July, Pfizer and its partner, the German company, BioNTech, conducted a late-stage clinical trial on the coronavirus vaccine. Half of the people in the experiment received the vaccine, while the rest received a placebo of the vaccine. Out of the 44,000-plus participants in the study, only 170 of them contracted the coronavirus.

An independent board of experts analyzed the data and found that the vaccine is at least 95% effective. Vaccines can typically take up to ten years to be fully researched and manufactured. However, in an unprecedented manner, Pfizer was able to fast-track the vaccine, alongside some other drug companies, Moderna and AstraZeneca.

Alfonso Alvarado, Chabot’s immunization coordinator, explained that in order to create a vaccine, scientists and manufacturers must first figure out the components of a virus and what the body needs to fight it. Vaccine trials are done in controlled clinical studies and are limited to a specific age group.

The Pfizer vaccine didn’t include pregnant women or children in their studies meaning they excluded these populations in the findings, which could impact the coronavirus’s effective rate down the road.

Pfizer’s current findings show that the vaccine is 95% effective when it’s second shot is administered after three weeks. Without the booster shot, its efficiency goes down to 52%. The yearly influenza shot is typically around 50%-60% effective.

According to Alvarado, the coronavirus vaccine effective rate could stay at 95% or it could drop lower, because we haven’t immunized everyone so we don’t know the response.

The flu vaccine has a lower effective rate because the virus mutates at a much faster rate and the flu strains change more frequently than the coronavirus. The influenza virus has millions of billions of different strains, so it’s difficult to figure out the type of strain that we’re exposed to, Alvarado clarified.

Herd immunity, a phrase being thrown around a lot more recently, is when most of the population is immune to a disease, and provides indirect protection against it. And in order for that to be achieved, at least 70% of the world population needs to be vaccinated.

“To end the pandemic, we need to end the transmission of the virus, and to do that we need to develop some kind of population-wide immunity,” said Dr. Katy Stephenson, a physician-scientist who specializes in infectious diseases and HIV immunology and does vaccine development at Harvard.

However, Alvarado stressed that it usually “takes a couple of weeks to get immune, depending on the vaccine. Once you’re actually in contact with that virus and you’re exposed to it, you may be protected against the most malignant part of the virus. But some patients build immunity from the vaccine and some don’t.”

Alvarado says that once people receive the vaccine, they should still follow CDC guidelines, meaning to continue to social distance and wear masks. He explains that just because people are given the vaccine, it doesn’t mean they have full immunity.

Pfizer’s chief executive says that it could have between 15 to 20 million doses of the vaccine available by the end of the year. Those who qualify for the initial dose have not been announced, however, those at a higher risk of infection or those more susceptible, are likely to have higher priority. This could include health care workers, like nurses and doctors, and older Americans who live in long-term care homes.

As of Tuesday, Dec. 8, a portion of people in the United Kingdom have already been administered the first shot of the Pfizer vaccine. Britain is trying to roll out the vaccination of tens of millions of people against Covid-19 in just a matter of months.

The U.S. could begin the rollout of the Pfizer vaccine as early as Dec. 14. Roughly 327,000 doses are expected to be available during the first round of vaccines that’ll arrive in California as early as Dec. 15. On top of that, Gov. Gavin Newsom announced that the state of California could receive a little more than two million doses of the vaccine by the end of December from both Pfizer and Moderna.

This comes at a time where 51 out of 58 of the counties in California are in the ‘purple-tier’, the most restrictive level on the state’s reopening tier system.

The likelihood of schools reopening in California for the 2020-2021 school year seems unlikely. As cases continue to go up, many counties are holding off on announcing the reopening of schools. It’ll also take some time for the majority of Californians to receive the vaccine, even then safety measures will still most likely be in place.