Pandemic Chronicles: a vaccine primer

It will be months before most washoe residents can be immunized

PHOTO/NEVADA NATIONAL GUARD: Chief Master Sgt. Jason Farnsworth, superintendent of the 152nd Medical Group of the Nevada Air National Guard, gets vaccinated on Dec. 17. Medical staff and other first responders are in the first tier for inoculations.

With the arrival of the COVID-19 vaccine in Washoe County, the end of the pandemic is in sight, but the road to that finish line is paved with long waits and continued precautions against virus transmission, according to the director of the Nevada State Health Laboratory.

Dr. Mark Pandori, lab director and an associate professor in the University of Nevada, Reno Medical School Department of Pathology and Laboratory Medicine, said drugs that will effectively treat COVID-19 infections are probably a long way off.

“Coming up with vaccines is easier than developing treatment drugs,” he said. “That takes years. We’re going to have to win this one on our own. The vaccine is probably the only way out of this.”

Pandori, who spoke at an Osher Life-Long Learning online program, cautioned that people who have received the vaccine or who have previously been infected will still have to observe pandemic precautions, such as social distancing and wearing masks in public. Because so little is known about transmission of the new virus, the length of immunity among people who have already been infected and other factors relating to the vaccine, an abundance of caution is the best practice.

“We just have to get to the finish line,” he said, and that’s “herd immunity.” For that to happen, the vast majority of the population needs to be vaccinated.

Reaching ‘herd immunity’

“If large numbers of people refuse to receive the vaccination it will have a gigantic impact,” Pandori said. “In general, we reach herd immunity when about 70% of the population has had the virus or have been vaccinated, (then) the virus can’t be-bop around very well because the places it jumps are all dead hosts. Then the virus can‘t spread in that community.”

PHOTO/UNR SCHOOL OF MEDICINE: Mark Pandori, Ph.D, biomedical sciences.

What it will take to reach that point remains a matter of guesswork. Communicable disease expert Dr. Anthony Fauci recently said it may take between 70 and 85 percent of the population to get vaccinated to reach herd immunity.

If too few members of a population don’t get vaccinated or aren’t otherwise immune, then the virus can actively find hosts and continue to spread in a community. “If you didn’t get vaccinated, you’ll get it,” Pandori said. “The goal is to reach herd immunity so we can have a normal life again. In the meantime, we’ll still need masks and social distancing. It’s going to take time.”

He said the virus is so new, no one can predict how long immunity lasts or whether the current vaccines will protect people from mutations of the virus. “People do get re-infected, but we don’t know how often,” he said. “We do know from other types of corona viruses that the concept of life-long immunity doesn’t seem to stick.” He noted that 15% of colds are caused by corona viruses and people can get colds repeatedly.

Three Americans got sick twice

One of the documented cases of someone being infected twice involves a 25-year-old Washoe County man. “He got it twice and he was sicker the second time,” Pandori said. “It could be that that second dose (of exposure) was overwhelming.” A 45-year-old Virginia man also got sicker on his second time around. The third U.S. double-infection case involved a nursing home patient in Seattle who survived a 40-day bout with the virus in April, but caught it again in July.

Genetic testing revealed the Seattle man had a different variation of the bug on his second time around.

“Vaccination immunity isn’t the same as natural immunity,” Pandori explained. He said the rare cases of re-infection may not apply. “We’ll see. In other cases, vaccination immunity is actually better than natural immunity, as (was determined) with the HPV and pneumonia vaccines.”

IMAGE/PIXABAY: Vaccines developed by Pfizer and Moderna are believed to be about 95% effective against coronavirus.

The two recently available vaccines for COVID-19 are the first of their kind using messenger RNA (mRNA), a generic code. He said RNA is in every cell of a human body, so allergic reactions that people have to certain drugs or to the way annual flu vaccines are made don’t come into play. He said the mRNA vaccines appear to be safe.

A new kind of vaccine

“What’s injected is not a live or a dead virus,” Pandori said. “It’s a segment of code, a molecule.” The code tricks the body into reacting as though it’s being invaded by the virus. The body’s immune system kicks in and learns to defeat in attack. “It’s your immune system that may make you feel a bit sick (after getting vaccinated),” he said. “That means it’s doing something; it’s working.”

Until 70% or more of the population is inoculated, the main tool for preventing infection and transmission is peoples’ own behavior.  Wearing a face mask can reduce an individual’s risk of infection by 70%. Keeping 6 feet away from people who are not in one’s household and avoiding spending time in enclosed rooms are the main defenses against the contagion. 

IMAGE/PIXABAY: Strands of DNA. The new vaccines work by using a snippet of code of what’s called messenger RNA, which carries genetic code from DNA to cells that make proteins that will kick off a patient’s immune response.

Pandori said that studies indicate infected people shed the virus for about nine days from the time symptoms begin. “Most infections occur indoors,” he said. “Outside, even a little bit of wind blows it away.” He used the metaphor of a wildfire, which needs fuel to spread, to explain virus transmission.

“The only way to get it is to be near each other,” he said. “It needs fuel to spread; humans are fuel.” The virus can live on surfaces, he noted, but the danger there is “touching things that are recently spoiled, then touching your face. That’s what the data say.”

Inoculations being given

Washoe County received its first shipment of a vaccine on Dec. 15, with 3,650 doses distributed within days. The vaccines require two injections about six weeks apart. Experts warn that vaccination does not provide instant immunity; it can take four to six weeks from initial dosing to achieve immunity and protection levels comparable to those in clinical trials. During that time it is still possible to contract an infection and get sick.

There is no data as to whether a vaccinated person who is protected against illness can still spread the virus. In addition, no one knows how effective existing vaccines will be against future mutations of the SARS-coV-2, the virus that causes COVID-19.

“We may be able to adjust the vaccine the way the flu vaccine is changed each season for a new strain,” Pandori said. “It would be a matter of changing the code.”

PHOTO/PIXABAY: COVID vaccines spark an immune response, creating antibodies to fight off future exposure to the virus.

State using a tiered system

In Washoe County, health officials are following their vaccine playbook to determine who gets the vaccines and when. The first two tiers focus on front-line workers. Tier 1 includes medical staff members and health care providers, public safety and emergency management personnel and long-term care facility staff and residents. Tier 2 includes teachers and others working in schools, public transportation, food banks and “essential retail workers.” The second tier also covers heath care support workers and prisoners.

The third tier encompasses people with underlying health conditions that increase their risk of severe COVID-19 infections, homeless people, and people older than 65 without additional risk factors.  The fourth and final tier includes healthy adults under age 65. The vaccines should be available to most county residents by the spring, officials said.

“We’re getting a lot calls from people with their opinions about who should be prioritized (in getting) the vaccine, and very often it’s them. It’s important for people to be patient and understand that the priorities are established by the state, following guidelines from the CDC. We are not making those decisions at the health district and we are not going to deviate from that tier structure.”

— Kevin Dick, Washoe County health officer, at a media briefing Dec. 23.

The pandemic to come

The virus is so new, scientists won’t know how long either natural immunity or vaccination immunity lasts until many more people receive a vaccine and there is more data on how well it works. “We don’t know how much gumption (the virus) has,” Pandori said.

While our attention is focused on ending the current pandemic, scientists like Pandori are already worried about the next one. He said such contagions have been so rare it’s been difficult to get the government or the public focused on investments and planning for outbreaks.

“The U.S. was not really ready for this and is still not ready for the next one,” he said. “If we had to deal with another pandemic we’d be in the same boat we were in nine months ago.”

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